Electrochemistry and Nanomaterials · Glassy carbon modified electrodes for comparison of wine...
Transcript of Electrochemistry and Nanomaterials · Glassy carbon modified electrodes for comparison of wine...
3rd Forum on Electrochemistry and Innovation
Electrochemistry and Nanomaterials
Universidade de Trás-os-Montes e Alto Douro
Vila Real
16, 17 of September 2013
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
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3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
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PROGRAM SCHEDULE 04
ABSTRACT INDEX 06
ABSTRACTS 11
LIST OF AUTHORS 63
LIST OF PARTICIPANTS 66
SPONSORS 71
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PROGRAM
16 September
12:00-14:15 Registration
14:15-14:30 Opening Ceremony
Theme A: "Electrochemistry in nanomaterials"
Chairpersons: Carlos Pereira and Ana Bettencourt
14:30-15:30 Plenary Lesson: PATRICK UNWIN
“New Directions in Electrochemical Imaging: Structure-Activity
Investigations and Patterning at the Nanoscale”
PL1
15:30-15:45 Keynote Lecture: ANA VIANA
“Functionalization and stable self-assemble of nanoparticles on
electrode surfaces”
KN1
15:45-16:10 Coffee-Break
Chairpersons: Jorge Correia and Cristina Oliveira
16:10-17:10 Plenary Lesson: DAVID FERMIN
“Reactivity of Pd Nanoshells: Feeling the Strain”
PL2
17:10-17:40 Oral Communication: LÚCIA BRANDÃO
Platinum-free electrocatalysts for oxygen reduction
OC1
17:40-17:50 Tributo to Luísa Abrantes
17:50-18:10 Oral Communication: VIRGÍNIA FERREIRA
“Noble-metal nanoparticles modified electrodes - electrochemical and
catalytic properties”
OC2
18:10-19:30 Poster Session
19:30 Porto d´Honra and Dinner (Panoramic Restaurant)
17 September
Theme B: "Nanomaterials for electrochemical devices"
Chairpersons: Luís Proença and Dulce Geraldo
9:00-10:00 Plenary Lesson: HERMAN AGUSTÍN COSTA GARCÍA
"Nanostructures on screen printed electrodes as novel
transducers for sensors”
PL3
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10:00-10:30 Keynote Lecture: CRISTINA DELERUE-MATOS
" Nanomaterial-based electrochemical sensors: the future trends for
analytical tools”.
KN2
10:30-10:50 Oral Communication: CÉLIA SILVEIRA
" Deconvolution of cytochrome c nitrite reductase electrochemistry
using MWCNTs with different surface chemistries”
OC3
10:50-11:15 Coffee-Break
Chairpersons: Carlos Silva and Fátima Bento
11:15-11:45 Keynote Lecture: MIKHAIL ZHELUDKEVICH
"“Smart” coatings for active corrosion protection based on multi-
functional micro and nanocontainers"
KN3
11:45-12:15 Keynote Lecture: MADALINA M. BARSAN
“Nanostructured modified electrodes and application
in sensors and biosensors”
KN4
12:15-12:35 Oral Communication: LÍDIA SANTOS
“Hydrothermal synthesis of nanoparticles of WO3 and its application in
electrochromic inkjet printed thin films”
OC4
12:35-13.05 Keynote Lecture: PIER PARPOT
“Electrocatalysts based on carbon nanotubes: application to
wastewater treatments”
KN5
13:05-13:15 Best poster award and Closing Session
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ABSTRACT INDEX
Ref. Title / Presenting Author Page
PL1
New Directions in Electrochemical Imaging: Structure-Activity Investigations and Patterning at the Nanoscale
Patrick R. Unwin
11
PL2 Reactivity of Pd Nanoshells: Feeling the Strain
David J. Fermin 12
PL3
Nanostructures on screen printed electrodes as novel transducers for sensors
Agustín Costa García
13
KN1
Functionalization and stable self-assemble of nanoparticles on electrode surfaces
Ana S. Viana
14
KN2
Nanomaterial-based electrochemical sensors: the future trends for analytical tools
Cristina Delerue-Matos
15
KN3
“Smart” coatings for active corrosion protection based on multi-functional micro and nanocontainers
Mikhail Zheludkevich
16
KN4
Nanostructured modified electrodes and application in sensors and biosensors
Madalina M. Barsan
17
KN5
Electrocatalysts based on carbon nanotubes: application to wastewater treatments
P. Parpot
18
OC1 Platinum-free electrocatalysts for oxygen reduction
K. Eblagon, Lúcia Brandão 19
OC2
Noble-metal nanoparticles modified electrodes - electrochemical and catalytic properties
V.C. Ferreira
20
OC3
Deconvolution of cytochrome c nitrite reductase electrochemistry using MWCNTs with different surface chemistries
Célia M. Silveira
21
OC4
Hydrothermal synthesis of nanoparticles of WO3 and its application in electrochromic inkjet printed thin films
Lídia Santos
22
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P1
Corrosion resistance of single wall carbon nanohorns as electrocatalyst support
Lúcia Brandão
23
P2
Development of 3D Dendritic Ni−Co Films: electrodeposition parameters and heat treatment effect
R.P. Silva S Eug nio Silva Carme im F ontemor
24
P3
Determination of plant-toxicity inductors metals at a rotating-disc bismuth film electrode by anodic stripping voltammetry
Ana. I. Matos, M. M. Rocha, M. M. M. Neto, L. L. Martins, M. P. Mourato
25
P4
Evaluation of radical scavenging activity of antioxidants by means of electrogenerated HO radical
Raquel Oliveira, D. Geraldo, F. Bento
26
P5
Screen Printed Electrodes Modified with Carboxylated Multiwall Carbon Nanotubes for the Analysis of Hydroquinone and Ascorbic Acid
Rui Gusmão, M.Fortes, R. Oliveira, D. Geraldo, F. Bento, F.Proença, C. Paiva
27
P6
Degradation of alizarin red promoted by electrogenerated HO radicals: A kinetic study
Fátima Bento, A. Vilas Boas, R. Oliveira, D. Geraldo
28
P7
A new approach to domoic acid detection
Dulce Geraldo, R. Oliveira, F. Bento, J. Gonzalez-Costas, E.Gonzalez-Romero
29
P8
Direct Methanol Micro Fuel Cell: Fabrication Process Using Microsystems Technologies
C.A. Faria, R. Sousa, L.M. Goncalves
30
P9
Trace metal interactions with CdTe/CdS quantum dots: an electrochemical study
José Paulo Pinheiro, C. Franco, R. Domingos
31
P10
Electrochemical biosensing platform using self-assembled multivalent nanoparticles
Rui Carvalho, E. Vrouwe, J.P. Pinheiro, A. Velders
32
P11
Glassy carbon modified electrodes for comparison of wine antioxidant properties
N. Dionísio, Cristina Oliveira
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P12
Modified electrodes for electrocatalysis: electropolimerisation based on binuclear metal complexes
Sara Realista, P. Martinho, A. Melato, M.J.Calhorda
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P13
Direct and catalyzed reduction of dissolved CO2 in aqueous media using a polymeric gas diffusion membrane
Rui Gusmão, C.Pereira
35
P14
Synthesis of lithium vanadium oxides nanoparticles by solution processing for electrochromic devices
A. Santos, L. Pereira
36
P15
Electrocatalytic properties of metalloporphyrins immobilized on platinum nanoparticles stably linked to gold surfaces
I. Almeida, A. S. Viana
37
P16 Functionalization of iron oxide nanoparticles for biosensors
F. Henriques, M.D. Carvalho, A.S. Viana 38
P17
Electrocatalytic Properties of Self-assembled Monolayers of Porphyrins and Chlorins Adsorbed from Phosphonic or Carboxylic Acid Groups on ITO
J. F. Cabrita, L. M. Abrantes, F. P Montforts, A. S. Viana
39
P18
‘Smart’ coatings as sensors based on nanocontainers
Frederico Maia, Alexandre C. Bastos, João Tedim, Mikhail L. Zheludkevich and Mário G.S. Ferreira
40
P19
Simultaneous Determination of Nickel and Cobalt, Using a Solid Bismuth Vibrating Electrode, by Adsorptive Cathodic Stripping Voltammetry
G. Alves , J. Magalhães, Helena M.V.M. Soares
41
P20
The role of gold nanoparticles on the sensitivity of a bi-enzymatic biosensor for carbamate pesticides determination
T.Oliveira, M. F. Barroso, S. Morais, M. Araújo, C. Freire, P. Lima-Neto, A. Correia, M.Oliveira, Cristina Delerue-Matos
42
P21
Electrochemical properties of a gold nanoparticles doped organic/inorganic hybrid matrix gel
C. Silva, S. Moreira, J. Silva, M. Costa, M. Gomes 43
P22
Immobilization of Metalloporphyrins onto Electrode Surfaces by Electropolymerization of Tailored and Conventional Monomers
Isabel M. Ornelas , C. Neves , M. Neves , A. Viana, J. Cavaleiro , J. Correia
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P23
Influence of Zeolite Particles and Inhibitor as Additive for Concrete in the Rebar Corrosion Protection C. Vicente ,A. S. Castela, R. Neves, M. F. Montemor
45
P24 New phenolic imidazole derivatives: evaluation of antioxidant activity
A.P. Bettencourt, F. Lobo, A. Leite, C. Correia, M. Carvalho, M. Proença 46
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P25
Gold nanoparticles-based biosensor for determination of amyloid beta-peptide
P. Carneiro, J. Loureiro, S. Coelho, C. Delerue-Matos, S. Morais, M. Pereira
47
P26
Application of a DNA-based biosensor for the electrochemical investigation of the effect of free radicals and antioxidants
S. Costa, D. Cruz, M. Barroso, M. Ramalhosa, A. Duarte, C. Delerue-Matos
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P27
Study of electrochemical properties of a protective film formed onto nickel when immersed in alkali metal solutions
Cilene Vicente, R. Duarte, A. Castela
49
P28 Development of an electrochemical aptasensor for protein detection
Sofia G. Meirinho, Luís Dias, Antonio. Peres, L. Rodrigues 50
P29
Modified Titanate Nanotubes Decorated with Nanocrystalline Bi2S3 as New Materials for Sensor Applications
J. F. Cabrita , O. C. Monteiro
51
P30
Disposable immunosensor with simple antibody orientation for label-free real-time detection of a cancer biomarker
Nádia S. Ferreira, M. Goreti F. Sales
52
P31
Smart Plastic Antibody Material for Hemoglobin Tailored by Silica Surface Imprinting and with Charged Binding Sites: Its use as Ionophore in Potentiometric Transduction
Ana P. T. Moreira, Felismina T.C. Moreira, M. Goreti F. Sales
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P32
Carnitine tailored Sensors on Surface Molecular Imprinting based on Graphene layers
Liliana A.A.N.A. Truta, Nádia S. Ferreira, M. Goreti F. Sales
54
P33
A Biomimetic Biosensor based on Poly(o-aminophenol) film for Cardiac Biomarker detection in Point-of-Care
F. Moreira, S. Sharma, R. Dutra, J. Noronha, A. Cass, M. Sales
55
P34
Organic-Inorganic Hybrid Sol-gel Coatings to Prevent Corrosion of Galvanized Reinforcing Steel
R. B. Figueira, E. V. Pereira, C. J. R. Silva, M. M. Salta
56
P35
Characterization of ZnO Nanoparticles on Electrode Surfaces by Electrochemical Techniques
José A. Ribeiro, P. Fernandes, C. Pereira, F. Silva
57
P36 Progress on studying the effect of alloying Pd with phosphorus on the ethanol electrooxidation
S. Salomé, R. Rego, M. C. Oliveira
58
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P37
An electrochemical impedance spectroscopy study of oxygen reduction kinetics on PdP alloys
Rosa Rego, Sónia Salomé, Maria Cristina Oliveira, J.C.S. Fernandes
59
P38
Building Biomimetic Lipid Raft Environments on Modified Gold for the Study of Bioactive Molecule-Membrane Interactions
Joaquim T. Marquês, Rodrigo F. M. de Almeida, Ana S. Viana
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PL1
New Directions in Electrochemical Imaging: Structure-Activity
Investigations and Patterning at the Nanoscale
Patrick R. Unwin, Kim McKelvey, Aleix G. Güell, Stanley C. S. Lai, Anisha N. Patel, Katherine E. Meadows, Julie V. Macpherson, Robert A. Lazenby, Binoy P. Nadappuram, Barak D. B. Aaronson, Changhui Chen, Gouhui Zhang, Anatoli Cuharuc and Alexander W. Colburn
Warwick Electrochemistry and Interfaces Group, Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK
[email protected] (www.warwick.ac.uk/electrochemistry)
Electrochemical imaging methods, such as scanning electrochemical microscopy (SECM) have had a significant impact in electrochemistry and interfacial chemistry, allowing reactions and fluxes to be measured and mapped locally.1 However, despite considerable effort, such methods have largely remained stuck with a resolution at the several µm scale. At Warwick, we have recently pioneered new techniques for electrochemical imaging, notably scanning electrochemical cell microscopy (SECCM)2 and contributed to the development of related methods,3 which allow us to examine electrochemical processes, and surface reactions generally, with unprecedented spatial resolution. This talk will introduce these methods and show how they can be used to probe electrochemical reactions at individual features at electrode surfaces, including steps, terraces and single catalytic nanoparticles. A particular focus of our work is new forms of carbon such as graphene and nanotubes, where our novel methods provide considerable new insights on the intrinsic activity and allow textbook models to be examined in detail. A major outcome of our work has been the clear demonstration that the basal surface of sp2 carbon materials (graphite, graphene and nanotubes) has much higher intrinsic activity than recognised previously. A further application of these methods is in patterning and nanofabrication and it will be shown how SECCM, in particular, allows the ready creation of multidimensional nanostructures (dots, nanowires, towers, etc.) of conducting polymers. We thank the European Union FP7 programme, through an ERC award (QUANTIF) and Marie Curie Fellowships, along with EPSRC, for supporting much of this research. We also acknowledge fruitful collaborations with colleagues listed in the references below. 1. Amemiya, S.; Bard, A. J.; Fan, F. R. F.; Mirkin, M. V.; Unwin, P. R. Annu. Rev. Anal. Chem., 2008, 1, 95. 2. See for example: (a) N. Ebejer, M. Schnippering, A. W. Colburn, M. A. Edwards & P. R. Unwin, Anal. Chem., 2010, 82, 9141. (b) M. E. Snowden, A. G. Güell, S. C. S. Lai, K. McKelvey, N. Ebejer, M. A. O’Connell, A. W. Colburn, and P. R. Unwin, Anal. Chem., 2012, 84, 2483. (c) A. G. Güell, N. Ebejer, M. E. Snowden, K. McKelvey, J. V. Macpherson, and P. R. Unwin, Proc. Natl. Acad. Sci. USA, 2012, 109, 11487. (d) A. G. Güell, N. Ebejer, M. E. Snowden, J. V. Macpherson and P. R. Unwin, J. Am. Chem. Soc., 2012, 134, 7258. (e) A. N. Patel, K. McKelvey and P. R. Unwin, J. Am. Chem. Soc., 2012, 134, 20246. (f) S. C. S. Lai, A. N. Patel, K. McKelvey and P. R. Unwin, Angew. Chem. Int. Ed., 2012, 51, 5405. (g) S. C. S. Lai , P. V. Dudin , J. V. Macpherson and P. R. Unwin, J. Am. Chem. Soc., 2011, 133, 10744. (h) B. D.B. Aaronson, C.-h. Chen, H. Li, M. T.M. Koper, S. C. S. Lai and P. R. Unwin, J. Am. Chem. Soc., 2103, 35, 3873–3880. 3. (a) Y. Takahashi, A. I. Shevchuk, P. Novak, B. Babakinejad, J. Macpherson, P. R. Unwin, H. Shiku, J. Gorelik, D. Klenerman, Y. E. Korchev, and T. Matsue, Proc. Natl. Acad. Sci. USA, 2012, 109, 11540-11545. (b) Y. Takahashi, A. I. Shevchuk, P. Novak, Y. Zhang, N. Ebejer, J. V. Macpherson, P. R. Unwin, A. J. Pollard, D. Roy, C. A. Clifford, H. Shiku, T. Matsue, D. Klenerman and Y. E. Korchev, Angew. Chem. Int. Ed., 2011, 50, 9638-9642.
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PL2
Reactivity of Pd Nanoshells: Feeling the Strain
V. Celorrio,a D. Plana,
a J. Florez,
b E. Pastor
b and David J. Fermin
a
a School of Chemistry, University of Bristol, Cantocks Close, Bristol BS8 1TS, UK
b Universidad de La Laguna, Dpto. de Química-Física, Avda. Astrofísico Francisco Sánchez
s/n, 38071 La Laguna (Tenerife), Spain
One of the most active areas of research in electrocatalysis is devoted to tuning the reactivity
of metal nanostructures supported on mesoporous carbon layers. Average particle size,
effective crystal orientation and chemical functional groups at nanoparticle supports are
among the parameters more widely targeted for catalyst optimisation. Tuning the composition
of binary or multimetallic nanostructures has also been investigated either in alloy or core-
shell configuration. The reactivity of these systems can be rationalized in terms of the so-
called electronic and geometric (strain) effects on the structure of d-orbitals [1-2]. A classic
example involves Pd-overlayers at Au surfaces, which have received significant attention over
the years in the context of hydrogen electrocatalysis and formic acid (HCOOH) oxidation [3].
In this contribution, we shall discuss the electrocatalytic activity of Pd nanoshells grown by
colloidal synthesis onto Au nanoparticles as a function of their effective lattice strain.
Reactivity studies are focused on CO and HCOOH electro-oxidation, as well as CO2
reduction.
Our studies based on selective area electron diffraction have shown that the effective strain of
Pd nanoshells at Au cores relaxes from 3.5 to 1% as the thickness increases from 1 to 10 nm
[4]. Recent electrochemical studies at carbon supported core-shell nanostructures indicate
that CO tolerance is significantly affected by the Pd thickness [5]. In-situ FTIR studies show a
shift of the CO oxidation towards more negative potentials as the strain of the Pd layer is
relaxed. Clear trends are also observed on the current density for the oxidation of HCOOH.
Finally, we will also demonstrate that strain exerts a strong influence on the Faradaic
efficiency for CO2 reduction in solution as revealed by differential electrochemical mass
spectrometry. The ensemble of experimental data also allows interrogating key mechanistic
aspects of these reactions.
References
1. J.K. Norskov, et al. Nat. Chem.1 (2009) 37
2. P. Strasser, et al. Nat. Chem. 2 (2010) 454; E. Santos, et al. Electrochim.Acta 55 (2010)
4346
3. L.A. Kibler, et al. Angew. Chem., Int. Ed. Engl. 44 (2005) 2080; A. Bonnefont, et. al. Cat.
Today 202 (2013) 70
4. M.G. Montes de Oca, et al. J. Phys. Chem. C 115 (2011) 10489
5. V. Celorrio, et al. J. Phys. Chem. C 116 (2012) 6275
Keywords: Core-shell nanostrucrures, Au-Pd, electrocatalysis, lattice strain effects.
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PL3
Nanostructures on screen printed electrodes as novel
transducers for sensors
Agustín Costa García
Department of Physical and Analytical Chemistry, Faculty of Chemistry, University of
Oviedo, Av. Julián Clavería 8, 33006 Oviedo, Spain
Our society demands new analytical tools combining requirements as suitable design, low
cost, portability, accuracy, selectivity and easy-to-use character. Adaptability to small sample
volumes is also a need. Electrochemical sensors are nowdays the type of device that better
adapts to social demand.
Conventional electrodes based on gold, platinum or carbon, are frequently used as sensor
transducers in many research papers. However, they are not very likely to become a useful
tool for commercial sensors in the clinical diagnosis field, food science or environmental
monitoring, since the contact with the sample normally invalidates them for future uses.
Screen printing techniques are making possible the mass production of screen printed
electrodes made of a several materials (gold, platinum, carbon…) and the miniaturization of
full electrochemical cells like those shown in Figure 1. They allow the design of new sensors
for wide range of fields of application.
In this communication especial attention will be paid to the description of the formation of
nanostructured screen printed electrodes, by means of several carbon materials, gold
nanoparticles in-situ generated or nanohybrides (carbon nanotubes-gold, or graphene-gold).
The application to the sensor and biosensor design will be highlighted.
Figure 1. Screen printed electrode
Keywords: Electrochemical sensors, screen printed electrodes, nanostructures, nanomaterials.
Pseudo-reference electrode
Working
electrode
Counter electrode
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KN1
Functionalization and stable self-assemble of nanoparticles on electrode
surfaces
Ana S. Viana
CQB, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de
Lisboa, Campo Grande, C8, 1749-016 Lisboa, Portugal
Surface modification by sulfur-metal interaction, involving nanoparticles, has been employed
in many applications such as biosensors, commonly prepared through a multi-step procedure.
In the last years, we have explored a one-step methodology to efficiently modify gold
surfaces, both flat [1,2] and nanostructured [3], through the use of carbon disulfide and amine
containing compounds. Their ready reaction originates a dithiocarbamate group which can be
strongly attached to a gold surface, in a bidentate N-C-S2 resonance structure [4]. This simple
approach has been performed in both organic or aqueous medium and can be regarded as an
alternative procedure to the use of thiolated self-assembled monolayers, with terminal groups
suitable for (bio)molecules attachment.
This work illustrates several examples of functionalization and surface attachment of gold,
platinum, tin oxide and magnetic iron oxide nanoparticles, with different sizes and
synthesized by chemical or hydrothermal methods. The chemical modifications range from
the covalent assemble of small pH sensitive electroactive molecules or metalloporphyrins
with catalytic activity, to the attachment of aminoacids, protein A for the specific binding of
Immuglobulin G, and enzymes (e.g. Laccase and Glucose Oxidase) aiming the preparation of
simplified biosensing interfaces. The redox behaviour of the modified electrodes is followed
by cyclic voltammetry, including the monitoring of the biological activity of enzymes.
Atomic Force Microscopy is used for the characterization of the nanoparticles before and after
modification and assemblage to the electrode surface.
[1] I. Almeida, A. C. Cascalheira, A. S. Viana, Electrochimica Acta 55 (2010) 8686.
[2] Y. Niu, A. I. Matos, L. M. Abrantes, A. S. Viana, G. Jin, Langmuir 28 (2012) 17718.
[3] I. Almeida, V. C. Ferreira, M. F. Montemor, L.M. Abrantes, A. S. Viana,
Electrochim. Acta 83 (2012) 311.
[4] H. Zhu, D. M. Coleman, C. J. Dehen, I. M. Geisler, D. Zemlyanov, J. Chmielewski, G. J.
Simpson, A. Wei, Langmuir 24 (2008) 8660.
Acknowledgments
M. de Deus Carvalho and O. Monteiro are acknowledged for providing the iron oxide and tin
oxide nanoparticles. Funding was obtained from FCT: PTDC/QUI/66612/2006 and PEst-
OE/QUI/UI0612/2013.
Keywords: Chemical modification, nanoparticles, carbon disulfide, dithiocarbamate
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KN2
Nanomaterial-based electrochemical sensors: the future trends for
analytical tools
Cristina Delerue-Matos
REQUIMTE, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua
Dr. Bernardino de Almeida 431, 4200-072 Porto, Portugal. *[email protected]; tel: +351
228340500; fax: +351 228321159.
Electrochemical transducers play an important role in analytical chemistry. A wide variety of
electrodes has been used as support to fabricate sensor devices, including carbon paste-,
glassy carbon- and gold electrodes. Known disadvantages of conventional electrodes such as
memory effects due to difficult, time-consuming and sometimes inefficient cleaning steps can
be overcome with the more recently developed screen-printed electrodes (SPEs). These SPEs
are good alternatives because their fabrication technology is well established which allows the
mass production of reproducible, inexpensive, customized and mechanically robust
electrodes. The modification of the (working) electrode's surface with nanomaterials increases
the performance of the sensors by providing a larger and more (bio-)compatible sensing
phase. Recent progress in the synthesis of nanomaterials and fundamental understanding of
their properties has led to significant advances in nanomaterial-based sensors. Examples of
nanomaterials used in the nanostructuration of electrode surfaces are carbon-based, such as
carbon nanotubes, carbon nanofibers, and graphene, gold and magnetic nanoparticles. This
nanostructuration leads to an increase of the produced electrochemical signal which
consequently results in a higher sensitivity and a lower detection limit. Moreover, there is a
continuous effort to miniaturize the instrumentation to operate and control the sensors which
facilitates in situ measurements. All these characteristics make nanomaterial-based
electrochemical sensors attractive tools for analytical chemistry, applying different
electrochemical techniques such as voltammetry, amperometry, potentiometry and
electrochemical impedance spectroscopy.
Therefore, electrochemical sensors have recently found extensive applications in
environmental, food, pharmaceutical, and clinical laboratories and also in commercial point-
of-care devices. The number of electrochemical sensors is ever increasing, being one of the
future trends for the development of analytical tools.
Keywords: nanomaterial; electrochemistry; sensor; analytical chemistry
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KN3
“Smart” coatings for active corrosion protection based on multi-functional
micro and nanocontainers
Mikhail Zheludkevicha, Joao Tedim
a, Mario G.S. Ferreira
a
a Department of Materials and Ceramic Engineering, CICECO, University of Aveiro,
3810-193 Aveiro, Portugal
The application of organic coatings is the most common and cost effective method for
corrosion protection and extension of service life of many metallic structures in corrosive
environments. However, the degradation processes rapidly develop once the disruption of the
protective barrier occurs. Therefore, an active protection based on the “self-healing” of
defects in coatings is necessary to attain a long-term effect.
The present paper brings a brief summary of recent works in the area of new multi-level
protective systems, based on the controlled release of anticorrosion species from “smart”
micro and nanocontainers incorporated into a polymer or hybrid coating matrix.
Nanocontainer (or nanoreservoir) is a nanosized volume filled with an active substance
confined in a porous core and/or a shell which precludes the direct contact between the active
agent and the adjacent environment.
Several types of nanoreservoirs of corrosion inhibitors, nanotraps and microcapsules with
water displacers have been recently developed, incorporated into coating systems and
assessed in terms of active corrosion protection. A multi-level self-healing approach
combining several damage prevention and restoration mechanisms within the same system,
including the entrapment of corrosive ions, corrosion inhibition and water displacement from
active defects, is here reviewed.
Keywords: self-healing, coating, corrosion, nanocontainer, inhibitor.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
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KN4
Nanostructured modified electrodes and application
in sensors and biosensors
Madalina M. Barsan, Krishna P. Prathish, Christopher M.A. Brett
Departamento de Química, Faculdade de Ciências e Tecnologia,
Universidade de Coimbra, 3004-535 Coimbra, Portugal
The use of carbon-based nanomaterials for electrode surface modification can lead to
promising substrates for construction of new, improved electrochemical sensors and
biosensors in which the nanostructure plays an important role. Among carbon-based
nanomaterials, graphene is an attractive material due to its excellent conductivity, feasibility
for microfabrication, high surface area, mechanical strength, optical transparency and
biocompatibility [1]. Pure graphene is a zero band gap semiconductor and chemically inert, so
that functionalization is required for its application as electrode material [2].
Functionalised graphene (G) and nitrogen doped graphene (NG) nanomaterials are excellent
candidates for electrocatalytic sensing of biomolecules and for developing biosensors, due to
their unique physicochemical and electronic properties [3]. The effect of G and NG
functionalization with acid (HNO3) or with base (KOH), on the electrochemical properties of
the modified electrodes will be shown.
Materials based on NG with the conducting polymer poly(3,4-ethylenedioxythiophene)
(PEDOT) and the redox polymer poly(neutral red) (PNR) were also synthesized and their
electrochemical features will be described.
Electrocatalysis towards important cofactors present in oxidase and dehydrogenase based
enzymes, β-nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide
(FAD+) will also be discussed, the regeneration of which is the crucial step during enzyme
reactions, and thence in biosensor performance. Applications in sensing and biosensing will
be presented.
[1]. L. Rodríguez-Pérez, M. A. Herranza, N. Martín, Chem. Commun., 49 (2013) 3721.
[2]. R. Lv, M. Terrones, Mater. Lett., 78 (2012) 209.
[3]. D. Genga, S. Yanga, Y. Zhanga, J. Yanga, J. Liua, R. Li, T. Sham, X. Sun, S. Ye, S.
Knights, Appl. Surf. Sci. 257 (2011) 9193.
Keywords: carbon nanomaterials, graphene, electrocatalysis.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
18
KN5
Electrocatalysts based on carbon nanotubes: application to
wastewater treatments
M.F. Pintoa, M. Ferreira
a, I.C. Neves
a, , A.M. Fonseca
a, L. Peixoto
b, A.G. Brito
b, R.
Nogueirab, O.S.G.P. Soares
c, J.J.M. Órfão
c, M.F.R. Pereira
c, J.L. Figueiredo
c and P. Parpot
a
aDepartamento de Química, Centro de Química, Universidade do Minho, Campus Gualtar,
4710-057, Braga Portugal. bIBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering,
University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal cLaboratório de Catálise e Materiais (LCM), Laboratório Associado LSRE/LCM,
Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto,
Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
The increasing awareness of water pollution with organic compounds, such as dyes, and their
long term effects has encouraged intensive efforts towards pollution abatement.
Electrochemical oxidation may constitute an alternative route to the existing methods.
Electricity may substitute some toxic redox agents and may permit the oxidation of pollutants
in mild conditions i.e. ambient temperature and atmospheric pressure. In recent years there
has been increasing interest in multiwalled carbon nanotubes (CNTs) as heterogeneous
catalyst supports [1] owing to their high surface area and high electrical conductivity. These
peculiar characteristics qualify CNTs as adequate electrocatalysts or as catalyst support
materials for the oxidative degradation of organic pollutants in wastewater [2]. In this context
the electrochemical oxidation of some refractory compounds like oxalic and oxamic acids,
some organic dyes and pesticides was investigated on mono and bi-metallic catalysts
supported on multiwalled carbon nanotubes (CNT) aiming at the total transformation of these
compounds into carbon dioxide and water. The electrochemical performance of metallic
electrocatalysts for nitrate reduction in wastewater was also evaluated having in mind a paired
electrolytic process. The electroreactivity of the pollutants on selected electrocatalysts was
studied by cyclic voltammetry. Kinetic parameters of the reactions were also determined
using this last technique. Exhaustive electrolyses were carried out to determine the
mineralization rates and the product distribution. Finally the use of CNT and metal modified
CNT as support material for anodic biofilm in microbial fuel cells was studied.
Acknowledgements: Support for this work was provided by projects NANO/NTec-
CA/0122/2007 and F-COMP-01-0124-FEDER-022716 financed by Fundação para a Ciência
e a Tecnologia (FCT), Portugal and FEDER, in the context of Programme COMPETE
[1] P. Serp, M. Corrias, P. Kalck, Appl. Catal. A, 253 (2003) 337-358.
[2] M. Ferreira, M.F. Pinto, O.S.G.P. Soares, M.F.R. Pereira, J.J.M. Órfão, J.L. Figueiredo,
I.C. Neves, A.M. Fonseca, P. Parpot, Electrochim. Acta, 60 (2012) 278-286.
Keywords: carbon nanotubes, wastewater treatment, organic pollutant oxidation, nitrate
reduction.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
19
OC1
Platinum-free electrocatalysts for oxygen reduction
Katarzyna Eblagon, Lúcia Brandão
LEPAE, Faculdade de Engenharia da Universidade do Porto, R. Dr. Roberto Frias, 4200-
465 Porto
The development of cheaper electrocatalysts for oxygen reduction reaction (ORR) and a
cathode more tolerant to methanol are very important for the development and
commercialization of direct methanol fuel cells.
In this work, ruthenium catalysts modified with selenium were prepared and
characterized. Two catalyst preparation methods were studied: reduction of the metal salt with
NaBH4 solution and reduction of the impregnated metal precursor with H2. The metal based
catalysts were modified with SeO2, using two methods: 1- pre-formed metal/carbon catalysts
were re-dispersed in xylene and SeO2 was added to the solution under reflux; and 2- the metal
precursor salt and SeO2 was co-impregnated on carbon black in a water/ethanol mixture and
reduced at 90 ° C using NaBH4. The catalysts were characterized using SEM with EDAX,
XRD, HRTEM and TG.
Results have shown that samples reduced with NaBH4 have smaller particle size and
narrower distribution of sizes. EDAX analysis of ruthenium co-precipitated with selenium
samples indicated that selenium was selectively reduced in the close proximity of ruthenium,
maybe even on the ruthenium surface. No regions with signals only from selenium were
found. XRD results show that a pure crystalline phase of hcp lattice of RuSe2 (pyrite) was not
obtained even at high annealing temperatures. Therefore it is assumed that the existing
modification is an amorphous skin of selenium on the surface of ruthenium nanoparticles.
Catalytic active layers based on different RuSe catalysts were spray dried on a
commercial gas diffusion layer. 1 cm2 electrodes were immersed in a 1.0 M H2SO4 oxygen
saturated aqueous solution and tested at room temperature, using a Ag/AgCl reference
electrode and a Dimensional Stable Anode (DSA, composed by RuO2, IrO2 and TiO2) as
counter electrode. Linear sweep voltammetry scans were performed at 2 mV s-1
from OCV up
to 0.0 V - 0.3 V vs RHE. ORR activity for different samples will be addressed and its
performance evaluated in terms of preparation method, post-annealing conditions and metal
dispersion. ORR activity of the different electrodes will be compared with activity from a
commercial electrode.
Acknowledgements:
L. Brandão is grateful to FCT for the post-doc grant (SFRH/BPD/41233/2007). The authors
acknowledge financial support through the project PTDC/CTM/108454/2008.
Keywords: oxygen reduction reaction, platinum-free electrocatalysts, chalcoge
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
20
OC2
Noble-metal nanoparticles modified electrodes - electrochemical and
catalytic properties
V.C. Ferreira, A.I.Melato, L.M.Abrantes
CQB, Chemistry and Biochemistry Department, Science Faculty of the University of Lisbon,
Campo Grande, 1749-016 Lisbon, Portugal
It is widely recognized that the electrochemical behaviour of electrodes can strongly
depend on its dimensions. In the past micro- and ultra-micro electrodes have shown that
problems associated namely with diffusion can be overcome and improved properties
achieved. Particles in the nanometer scale also display properties that are different from bulk
materials [1,2]. The enhancement of mass transport, signal-to-noise ratio, high effective
surface area and control over the electrode microenvironment makes them attractive for
electrochemists. When immobilized, e.g. on indium tin oxide or conducting polymers (CPs),
advantages can be taken from the electrocatalytic properties of NPs.
The surface structure, size and crystallographic orientation of the NPs and the
presence of adsorbed species play an important role on the electrochemical response of such
materials [3]. In fact, in this work it is shown that the electrochemical behaviour can be tuned
by using surfaces with distinct crystallographic orientation and/or size, by selectively
block/exposure specific surface domains within a surface.
The conducting polymers offer a suitable matrix for the immobilisation of NPs, either
by electrodeposition, electroless precipitation or by simple immersion in colloidal suspensions
[4,6]. In the last case advantage is frequently taken from the interactions between the polymer
functional groups and the particles, often of noble metals such as gold, platinum, palladium
and silver. In the particular case of thiophene and its derivatives, the presence of sulphur
atoms in the polymer structure enables specific and stable interactions through sulphur-metal
bonding. The electrocatalytic activity of CPs-NPs modified electrodes can be highly improved
as compared with pristine polymers and bulk electrodes.
Keywords: Noble-metal nanoparticles, crystallographic orientation, conducting polymers,
electrocatalytic activity.
Acknowledgments
The financial support from Fundação para a Ciência e Tecnologia, SFRH/BPD/69526/2010
and SFRH/BPD/77404/2011 is gratefully acknowledged.
References
[
1] M.-C. Daniel, D. Astruc. Chem. Rev. 104 (2004) 293.
[2] C.M. Welch, R.G. Compton, Anal. Bioanal. Chem. 384 (2006) 601.
[3] V.C. Ferreira, J. Solla-Gullón, A. Aldaz, F. Silva, L.M. Abrantes, Electrochim. Acta 56 (2011)
9568. [
4] A. Mourato, S. M. Wong, H. Siegenthaler, L. M. Abrantes , J. Solid State Electrochem. 10 (2006)
140.
[5] V.C. Ferreira, A.I. Melato, A.F. Silva, L.M. Abrantes, Electrochem. Comm. 13 (2011) 993.
[6] V.C. Ferreira, A.I. Melato, A.F. Silva, L.M. Abrantes, Electrochim. Acta 56 (2011) 3567.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
21
OC3
Deconvolution of cytochrome c nitrite reductase electrochemistry using
MWCNTs with different surface chemistries
Célia M. Silveira
a, Marta Pimpão
a, Humberto A. Pedroso
a, Patrícia R.S. Rodrigues
a, José J.G.
Mouraa, Manuel F.R. Pereira
b, M. Gabriela Almeida
a,c
a REQUIMTE – Departamento de Química, CQFB, Faculdade de Ciências e Tecnologia,
Universidade Nova de Lisboa, 2829-516 Caparica, Portugal. bLCM – Laboratório de Catálise e Materiais, Laboratório Associado LSRE/LCM,
Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, R.
Dr. Roberto Frias, 4200-465 Porto, Portugal c Instituto Superior de Saúde Egas Moniz, Monte de Caparica, 2829-511 Caparica, Portugal
Carbon nanotubes (CNTs) are among the most used nanostructured materials in the field of
(bio)electrochemistry. They have demonstrated remarkable behavior in electroche-mical
studies as electrocatalysts and in facilitating protein direct electrochemistry. This has
contributed for CNTs successful use in electrochemical sensors and biosensors [1]. The
surface functionalization of the CNTs is frequently employed to improve their
biocompatibility and electroactivity. The most common method is chemical oxidation using
strong acids, which is usually associated with the introduction of reactive oxide functional
groups [2]. Typically, higher currents, lower overpotentials and enhanced electron transfer
rates are observed with the modified materials [3].
This work reports the use of multi-walled carbon nanotubes (MWCNTs) presenting different
surface chemistries as electrode modifiers for the direct electrochemistry of the multihemic
nitrite reductase (ccNiR) from Desulfovibrio desulfuricans ATCC 27774. The carbon
nanotubes dispersions were prepared in aqueous media and deposited on pyrolytic graphite
(PG) electrodes, following a layer-by-layer methodology; the resulting randomly entangled
MWCNTs bed was coated with a ccNiR film. The electrocatalytic properties of each material
were then assessed by cyclic voltammetry, either in the presence or absence of ccNiR’s
substrate. A comparison between the different oxidized MWCNTs indicated that the
combination of higher surface area, low oxygen content and less acidic functional groups
favored enzyme catalysis, highlighting the importance of surface conditions to enzyme
reactivity. Results also suggest that the CNTs containing less oxygen functionalities could
better plug into the active site of ccNiR. These nanotubes are a promising material for the
deconvolution of the complex electrochemical signals of the multihemic enzyme, allowing the
isolation of the catalytic centre response.
References:
[1] J. Wang (2005) Electroanalysis 17, 7.
[2] R.L. McCreery (2008) Chem. Rev. 108, 2646.
[3] J.J. Davis, K.S. Coleman, B.R. Azamian, C.B. Bagshaw, M.L. Green (2003) Chem. Eur. J.
9, 3732.
Keywords: multi-walled carbon nanotubes, surface oxides, direct electron transfer, nitrite
reductase.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
22
OC4
Hydrothermal synthesis of nanoparticles of WO3 and its application in
electrochromic inkjet printed thin films
Lídia Santos, P. Wojcik, L. Pereira, R. Martins, E. Fortunato
CENIMAT/I3N, Departamento de Ciência de Materiais, Faculdade de Ciências e Tecnologia,
Universidade Nova de Lisboa and CEMOP/UNINOVA, Campus da Caparica, 2829-516
Caparica – Portugal
Tel. +351 212948562, Fax. +351 212948558
E-mail: [email protected], [email protected]
Although, tungsten oxide has been widely reported as a promising inorganic electrochromic
material not many studies have been made that describe the influence of shape and
nanoparticles crystallinity on the EC performance. By controlling these factors, one could
design a material with optimal EC behavior.
In this work WOx nanoparticles with different characteristics were obtained by hydrothermal
synthesis of sol-gel precursor (peroxotungstic acid) using metallic tungsten as the starting
material. It was observed that the amount of hydrochloric acid and time of the process were
the critical parameters in a synthesis of monoclinic WO3 nanoslabs and/or orthorhombic
WO3.0.33H2O nanorods.
The resulting nanocrystals were dispersed in aqueous alcoholic solution and then inkjet
printed on ITO coated flexible PET substrates. Subsequently, the sol-gel precursor was also
printed to cover the nanostructures previously deposited. This innovative approach enables to
deposit dual-phase a-WO3/WOx thin films in a low temperature two-step process, which
irrespective to nanoparticles characteristics outperform their amorphous analogues, owing to
their superior electrochemical properties. Nevertheless, dual-phase films with orthorhombic
WO3.0.33H2O nanorods presented a superior electrochromic performance which can be
explained by the higher active surface area (38 m2/g) combined with the coordinated water
molecules from this polymorph.
Keywords: Tungsten oxide, printing deposition, electrochromic, thin film.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
23
P1
Corrosion resistance of single wall carbon nanohorns as electrocatalyst
support
Lúcia Brandão
LEPAE, Faculdade de Engenharia da Universidade do Porto, R. Dr. Roberto Frias, 4200-
465 Porto
The corrosion resistance of carbon based electrocatalyst supports in PEMFC is one of the
most important aspects besides electrode activity, and mainly at the cathode side.
Single wall carbon nanohorns (SWNH) are similar to carbon nanotubes presenting a
conic tip instead of the half fullerene cap at the top of the carbon tube; moreover they are
much cheaper to produce [1].
Previous works, developed at LEPAE, on the use of SWNH as electrocatalyst support
in fuel cells, have shown an increased performance of the SWNH based electrodes in
comparison with a carbon black support based electrode. A 60 % increase in performance was
observed for both PEMFC and DMFC at 50 ºC [1, 2]. In-situ EIS analysis indicated that the
major improvement in PEMFC performance was related to the cathode kinetics in the SWNH
sample [2]. In accordance, ex-situ linear sweep voltammograms for oxygen reduction
indicated that SWNH based electrode performs better than the carbon black one for voltages
lower than 0.65 V vs RHE [3]. Regarding methanol oxidation, ex-situ cyclic voltammetry
experiments have also indicated a higher electrochemical activity towards methanol electro-
oxidation and a higher tolerance to carbonaceous species accumulation for the SWNH based
electrode [3].
At high temperature fuel cell operation, 160 ºC, SWNH based electrodes showed a
similar peak power density to the carbon black based one despite the higher ohmic resistance.
Moreover, the SWNH based anode presented a lower charge transfer resistance than the
correspondent carbon black but similar cathode charge transfer resistance [4]. More recently,
experiments in vapour phase DMFC, at 160 ºC, also showed the improved performance of the
SWNH electrode besides presenting longer fuel cell stability during operation [3].
In this work, the corrosion resistance of SWNH and carbon black supporting Pt
electrocatalysts is addressed. An accelerated corrosion test, at 1.5 V vs NHE, was applied to
electrodes based on both the carbon supports. The corrosion extension history of each
electrode, at room temperature, was followed by electrochemical surface area measurements.
A commercial Pt electrode was also evaluated for comparison purposes.
Acknowledgements:
L. Brandão is grateful to FCT for the post-doc grant (SFRH/BPD/41233/2007) and for
financial support through the project PTDC/CTM/108454/2008.
References:
[1]- J. Mat. Sci., 46, 2011, 7198–7205; [2]- J. Nanosci. Nanotech, 11, 2011, 9016-9024; [3]-
Inter. J. Hydrogen Energy, 2012, 37 (24), 19073-19081; [4]- J. Electrochem. Soc, 158 (4),
2011, B394-B401.
Keywords: SWNH, fuel cells, carbon support, corrosion resistance.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
24
P2
Development of 3D Dendritic Ni−Co Films: electrodeposition parameters
and heat treatment effect
R.P. Silvaa, . ug nio
a, T. M. Silva
a,b, M.J. Carmezim
a, c, M. F. Montemor
a,d
a
bDepartamento de Engenharia Mecânica, Instituto Superior de Engenharia de Lisboa,
Portugal c
Portugal d
Lisboa, Portugal.
Electrodeposition is a widespread technique for the production of both decorative and
functional coatings that by controlling the process parameters (applied current/potential and
deposition time) and electrolyte composition enables the fabrication of films with tailored
morphology and chemical composition.
Electrodeposition is therefore a simple, low-cost technique for the production of
nanostructured transition metal films with tridimensional architectures. These materials have
gathered increasing interest due to their applications in catalysis, energy storage and
conversion, etc. where a high specific area is a key characteristic.
In this work, co-deposition of nickel and cobalt was carried out on austenitic stainless steel
(AISI 304) substrates by imposing a square waveform current in the cathodic region. The
influence of the applied current density on the morphology and chemical composition of the
Ni−Co films was investigated by scanning electron microscopy and energy dispersive X-ray
spectroscopy and X-ray diffraction. By applying optimised deposition conditions, a stable,
fully developed, and open porous three-dimensional (3D) dendritic structure was obtained.
The electrochemical behaviour of the materials was evaluated by cyclic voltammetry and
chronopotentiometry in order to assess their application as electrodes for supercapacitors.
Selected Ni-Co films were oxidized by heat treatment at temperatures between 150 and 900
C. The influence of the temperature in the phase composition and electrochemical behaviour
of the Ni-Co films was studied.
Keywords: electrodeposition; Ni-Co alloys; dendritic structure; energy storage
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
25
P3
Determination of plant-toxicity inductors metals at a rotating-disc bismuth
film electrode by anodic stripping voltammetry
Ana. I. Matosa, M. M. Rocha
a, M. M. M. Neto
a, L. L. Martins
b, M. P. Mourato
b
aCentro de Ciências Moleculares e Materiais, Faculdade de Ciências, Universidade de
Lisboa, Edifício C8, Campo Grande, 1749-016 Lisboa, Portugal
Telefone: +351 21 750 0000, Fax: +351 21 750 0088, Email: [email protected] bUnidade de Investigação Química Ambiental - UIQA, Instituto Superior de Agronomia,
Universidade Técnica de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal
Telefone: +351 21 365 3426, Fax: +351 21 365 3195, Email: [email protected]
In the last decades, the growing concern with contamination of aquatic and soil life by
toxic metals as copper, cadmium, mercury and others, and their potential damaging effect on
human health, promote the development of precise and accurate analytical methods.
Stripping techniques have demonstrated to be suitable approaches to determine trace
metals in environmental samples due to their high sensitivity, excellent detection limits,
capacity to multielement determination and low cost [1,2]. Bismuth film electrodes (BiFE)
appeared as an attractive option to replace mercury electrodes. Despite similar
electrochemical characteristics in terms of potential window and ability to electrodeposit
other substances on its surface, bismuth offers others advantages as an electrode material
including low toxicity, well defined and undistorted stripping signal, excellent resolution,
good stability under hydrodynamic conditions and is less sensitive to oxygen interference than
mercury electrodes [1-3].
The purpose of this work is the simultaneous speciation of heavy metals in samples of
plant extracts, exploring the potentialities of a rotating-disc bismuth film electrode. An in situ
plated bismuth film electrode was applied for Cd and Cu determination, in acetate buffer
solution (pH 4.6), by square wave anodic stripping voltammetry (SWASV); it was
successfully used to obtain calibration curves, enabling the simultaneous determination of Cd
and Cu, reoxidized at potentials values more negative and more positive than Bi(III)
reoxidation potential, respectively. Finally, this method allowed the speciation of Cu and Cd
at low concentration levels in samples of plant nitric extracts.
Keywords: Bismuth electrodes, stripping voltammetry, speciation of heavy metals.
Acknowledgements: The authors acknowledge FCT for the financial support: PTDC/AGR-
AAM/102821/2008.
References
[1] G. M. S. Alves, J. M. C. S. Magalhães, H. M. V. M. Soares, Electroanalysis 23 (2011)
1410.
[2] E. O. Jorge, M. M. Rocha, I. T. E. Fonseca, M. M. M. Neto, Talanta 81 (2010) 556.
[3] I. Cesarino, C. Gouveia-Caridade, R. Pauliukaitè, E. T. G. Cavalheiro, C. M. A. Brett,
Electroanalysis 22 (2010) 1437.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
26
P4
Evaluation of radical scavenging activity of antioxidants by means of
electrogenerated HO radical
Raquel Oliveira, Dulce Geraldo, Fátima Bento
Departamento de Química da Universidade do Minho, Campus de Gualtar, 4710-057 Braga
Hydroxyl radical is one of the most reactive radicals. The electrochemical generation of
hydroxyl radical by oxidation of water can be achieved using different anode materials. The
adsorption of HO radicals at the anode surface has a significant effect on their reactivity.
Using materials such as BDD, electrogenerated hydroxyl radicals are weekly adsorbed
whereas strongly adsorbed radicals are formed at Pt.
Although most of the available studies deal with high oxidation power anodes for the
degradation of pollutants, the use of anodes with low oxidation power can have important
applications particularly when a certain degree of selectivity is required for oxidation.
In this context electrochemically-generated hydroxyl radical was applied for the evaluation of
antioxidant scavenging activity. A set of species with antioxidant activity was oxidized by
galvanostatic electrolyses using a fairly oxidized Pt anode in conditions of O2 evolution. In
such conditions the consumption of species was not limited by mass transport but by the
oxidation kinetics of both charge transfer and reaction with HO radicals. Information
regarding the rate constant of the reaction of antioxidants with electrogenerated HO radicals
was obtained by means of the apparent rate constant variation with electrolysis current
density. Scavenger activity of the analysed antioxidants estimated by the kinetic parameter
2/, OHOR kk was ordered as follows: gallic acid, trolox > ascorbic acid > caffeic acid. The
method was applied successfully in synthetic solutions and in a green tea based beverage.
Keywords: Antioxidants, scavenging activity, HO radical generation, ascorbic acid, phenolic
compounds
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
27
P5
Screen Printed Electrodes Modified with Carboxylated Multiwall Carbon
Nanotubes for the Analysis of Hydroquinone and Ascorbic Acid
Rui Gusmãoa,b
, Marta Fortesa, Raquel Oliveira
a, Dulce Geraldo
a, Fátima Bento
a, Fernanda
Proençaa, Conceição Paiva
b
aCentro de Química, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal
bInstituto de Polímeros e Compósitos/I3N, Universidade do Minho, Campus de Azurem, 4800-
058 Guimarães, Portugal
Carbon nanotubes (CNT) have demonstrated to be advantageous in electrochemical
applications such as in energy storage devices and sensors. The presence of oxygenated
carbon species, especially carboxylic acid moieties, together with metallic impurities are
identified as chief factors for the catalytic properties of CNTs. The oxygen-containing groups
are introduced randomly at the surface of CNTs by strong mineral acid treatment. These
factors can be of extreme importance for the construction of biosensors based on carbon
nanomaterials.
In this study, multiwalled carbon nanotubes (MWCNTs) were chemically shortened and
carboxylated by treatment with nitric acid for metal impurities removalusing a method
described in the literature, originating MWCNT-COOH. Ethanol suspensions of MWCNT-
COOH at different concentrations were used to modify the surfaces of commercially available
screen-printed electrodes (SPEs).
The SPEs modification with MWCNT-COOH was optimised and it was applied in order to
obtain a reproducible electrochemical response. The morphology of the MWCNT-COOH
modified SPEs was characterized by Scanning Electron Microscopy. Characterization of the
CNT film generated on the surface of the working electrode and stability studies were carried
out with potassium hexacyanoferrate. Results are compared with those obtained for
commercially available carbon SPE and SPE-MWCNT.
Effect of solution acidity on the peak current and potential of the substances was studied at
pH 3 and 7 where a correlation with the dissociation degree of carboxyl groups at the
MWCNTs on the electrode surface occurs.
The catalytic properties of the MWCNT-COOH-modified SPEs as well as their analytical
advantages as voltammetric detectors are discussed through the analysis of ascorbic acid (AA)
and hydroquinone (HQ).
Keywords: Carboxylated Multi-Wall Carbon Nanotubes, Hydroquinone, Ascorbic Acid,
Potassium Hexacyanoferrate, Screen Printed Electrode.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
28
P6
Degradation of alizarin red promoted by electrogenerated HO radicals: A
kinetic study
Fátima Bento, Ângela Vilas Boas, Raquel Oliveira, Dulce Geraldo
Departamento de Química da Universidade do Minho, Campus de Gualtar, 4710-057 Braga
Alizarin Red (AR, 1,2-dihydroxyanthraquinone) is a dye used in textile industry since early
antiquity. Nowadays it is used in several biochemical assays in studies involving bone
growth, osteoporosis, bone marrow, calcium deposits, cellular signaling, gene expression,
tissue engineering, and mesenchymal stem cells.
Reactions of electrochemically generated hydroxyl radicals, by the oxidation of water, depend
on the reactivity of these radicals according to their adsorption degree at the anode surface. At
Pt HO radicals keep strongly adsorbed and display lower reactivity than those formed in
anodes like BDD. This effect as been already demonstrated by means of a kinetic study of
benzoic acid and p-hydroxybenzoic acid oxidation.
The study of the AR oxidation by HO radicals can bring important insight on the reactivity of
chemical functions such as aromatic rings, hydroxyl and carbonyl groups, that are common in
antioxidant molecules. Therefore, using a single molecule it is possible to investigate the
relative reactivity of these functional groups towards HO radical in identical conditions of
surface coverage, what cannot be warranted when the different molecules are considered.
The AR UV–Vis absorption spectrum displays three distinct peaks corresponding to the
anthracene ring, the carbonyl groups and quinonyl. Therefore by means of the absorbance
variation of the three UV-vis bands it was possible to evaluate the reactivity of the different
functional groups.
Keywords: Alizarin red, hydroxyl radicals, platinum, dye removal
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
29
P7
A new approach to domoic acid detection
Dulce Geraldoa, Raquel Oliveira
a, Fátima Bento
a, Javier Gonzalez-Costas
b, Elisa Gonzalez-
Romerob
a Departamento de Química da Universidade do Minho, Campus de Gualtar, 4710-057 Braga
b Universidad de Vigo, Vigo, Spain
The standard method for detection of marine toxins in bivalve is based on a mouse bioassay
that presents several disadvantages such as its cost, non-specificity, time analysis and of
course etic constraints. On the other hand regulation has been modified by the European
Commission 15/2011 on January 10th, 2011, replacing Regulation (EC) No 2074/2005 and
mouse bioassay will be banned from December 31, 2014. The development of new methods
for a rapid screening for detection of toxins is highly needed. Electrochemical sensors are
adequate for the development of user-friendly analytical methods that could therefore be used
in a daily base by fisherman.
In this work, we present a new strategy for the detection of domoic acid (amnesic toxin) based
on the functionalization of carbon screen printed electrodes (SPE) and SPE modified with
carbon nanotubes (CNTs). The functionalization is based in the immobilization of diazonium
ion generated by the 4-nitroaniline diazotization with sodium nitrite in hydrochloridric acid.
Although DA is not electroactive, it can be detected by means of a redox probe K4(FeCN)6,
which electrochemical response depends on the concentration of DA immobilized on a
functionalized SPE. Preliminary work has shown the possibility to carry out the
immobilization without the use of bifunctional agents, such as carbodiimides, n-
hydroxysuccinimide, that facilitates the bond between -NH2 and -COOH groups simplifying
the design of the sensor. Experimental variables such as pH, temperature and time were
optimized. Peak potential shift and enhancement of current intensity were analyzed.
Keywords: Domoic acid, toxins, carbon screen printed electrodes, SPE modified with carbon
nanotubes
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
30
P8
Direct Methanol Micro Fuel Cell: Fabrication Process Using Microsystems
Technologies
C.A. Faria, R Sousa, L.M. Goncalves
Algoritmi Centre, University of Minho, Guimarães, Portugal
In our days fuel cells are considered the next step for energy due to its efficiency and low
environmental impact. The electronic devices tend to decrease its size, perform more
functions, and provide more power in a smaller space. We get to a point where we need to
supply system with high power density, efficiency and low weight. It is in this context that the
fuel cell can be used. But to apply the fuel cells in electronics, transport systems and in other
applications, it is necessary that the price of this technology becomes significantly lower.
In this work we analyze the possibility of producing the fuel cell with the manufacturing
techniques used in micro fabrication and having as main raw material silicon, for being one of
the most abundant and cheaper. The possibility of being able to use silicon for fabrication of
fuel cells, will allow to place a unit power generation inside of electronic circuits and produce
smaller fuel cell modules.
A micro direct methanol fuel cell was fabricated without membrane using the silicon substrate
as the anode and cathode, applying the M M manufacturing techniques. Using a 2” wafer as
substrate, channels were fabricated by dicing. On these channels, 200nm of gold was
deposited by thermal evaporation, to create the collector contacts (a prior deposited thin layer
of titanium promotes adhesion of gold film). Cathode and anode thin-film of platinum were
deposited by e-beam, and a a thin-film of ruthenium covers the anode. After manufacture the
components, we proceeded to assembly and testing of the respective micro fuel cell. This fuel
cell is under testing. We concluded that it is possible to construct fuel cells using silicon in a
dicing process and thin-film technology.
Keywords: Fuel-Cell, DMFC, Microsystem, Energy, MEM
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
31
P9
Trace metal interactions with CdTe/CdS quantum dots: an
electrochemical study
José Paulo Pinheiro*,a, Cristiana Franco
b, Rute F. Domingos
b
a IBB/CBME, DQF/FCT, Universidade do Algarve, Faro, Portugal
b CQE, Instituto Superior Técnico/Universidade Técnica de Lisboa, Lisboa, Portugal
The work presented here is part of a larger project to evaluate the environmental risk of
several nanoparticles (e.g. ZnO, CdTe/CdS) towards exposure to Chlamydomonas reinhardtii.
Special emphasis is placed on quantitatively determining the role of the medium properties,
including pH, interactions with inorganic ligands and NOM on the dissolution/aggregation
behavior of the nanoparticles.
Polyacrilic acid stabilized CdS-capped CdTe quantum dots were studied. The stock solution
contains a total cadmium concentration of 0.0257 + 0.0005M, and the particle size (AFM) is
5.7±0.4 nm.
The aim of this particular study was to understand the interaction of the stabilizer (PAA) with
the cadmium ions either originated from the QD dissolution or added to the solution. The free
and bound cadmium concentrations in solution were determined by Scanned Stripping
Chronopotentiometry (SSCP) and Absence of Gradients and Nernstian Equilibrium Stripping
(AGNES),
In the first set of experiments we evaluated the effect of pH in the stability of the QD. Studies
were performed at pH 4.5, 6.0 and 8.5 in buffered medium, 10 mM ionic strength, 48h
exposure, for a NP concentration equivalent to 1.0 M of Cd.
The highest QD dissolution (i.e., percentage of Cd dissolved from the QD related to the total
Cd in the QD) was obtained at the more acidic pH (52 %). Dissolution of the QD was higher
at pH 8.5 than at pH 6.0 (24 vs. 4 %), which is the result of the increasing PAA ability to
complex the dissolved Cd leading to a further QD solubility until the equilibrium is reached.
At pH 8.5 we also observed a significant contribution of the PAA (carboxyl groups) to the
dissolved cadmium binding while below pH 6.0 that influence was negligible.
Keywords: Quantum dots, SSCP, AGNES, metal speciation, PAA
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
32
P10
Electrochemical biosensing platform using self-assembled multivalent
nanoparticles
Rui Carvalhoa, Elwin Vrouwe
b, J.P. Pinheiro
c, A. Velders
d
a,b
Micronit Microfluidics, Enschede, The Netherlands cUALG, CBME, Algarve, Portugal
dWUR, Wageningen, The Netherlands
Herein we report the manufacture of a novel nanoparticle based sensor to measure blood
clotting with commercial applications.
Nanoparticles are becoming extremely useful building blocks for the fabrication of
ultrasensitive optical and electrochemical nanosensors. Among these applications, the use of
Au nanoparticles as colorimetric sensors is gaining much attention owing to the possibility of
attaining high sensitivity with unsophisticated transducers. A common strategy for
biodetection with Au nanoparticles is to modify their surface with bioresponsive ligands,
which trigger the assembly or disassembly of the nanoparticles upon recognition by the target
biomolecule, for example, an enzyme.[1]
The key step of this method is to bind the bioresponsive ligands to the surface of the
nanoparticles through weak host–guest interactions; stronger multivalent interactions between
nanoparticles then lead to the formation of nanoparticle clusters. Recognition by the effector
biomolecule disrupts the multivalent network, and competition with a monovalent guest
amplifies the dispersion of the nanoparticles as the signal of the bioassay. Using linker
libraries in conjunction with multivalent β-cyclodextrin decorated gold nanoparticles will
provide with a novel sensing method for detecting relevant enzymes. Immobilization of these
aggregates in microfluidic channels, a portable enzyme sensor will be produced. By using
electrochemical techniques we can increase the sensing complexity and accuracy of the chip.
1. de la Rica, R., et al., Multivalent Nanoparticle Networks as Ultrasensitive Enzyme Sensors. Angewandte Chemie-International Edition, 2011. 50(25): p. 5703-5706.
Keywords: biosensor, nanoparticles, microfluidics, aggregation, surface plasmon resonance,
impedance, competition assay
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
33
P11
Glassy carbon modified electrodes for comparison of wine
antioxidant properties
Natália Dionísio, Cristina Oliveira
Departamento de Química/CQ-VR, Universidade de Trás-os-Montes e Alto Douro (UTAD),
Portugal
The ability of voltammetric techniques to evaluate the antioxidant capacity of the food
samples is well documented in the literature [1,2]. However, it was recently demonstrated that
despite the advantages of voltammetric techniques to evaluate the antioxidant capacity of food
samples, these were unable to distinguish wines containing low antioxidant capacity (e.g.
white, muscatel and tawny wines) [3].
This work reports preliminary experimental findings to improve the sensitivity of the cyclic
voltammetric technique for antioxidant determination of wines containing low concentration
of polyphenols. To achieve this purpose glassy carbon modified electrodes with carbon
Vulcan® (GCE/Vulcan®) and Ag nanoparticles supported on the carbon Vulcan
(GCE/Ag/Vulcan®) have been used. The method has been developed using gallic acid (GA)
as a phenolic acid model compound in acetate-acetic acid buffer (pH 4) and phosphate buffer
(pH 7), Figure 1. The results indicate that the electrochemical response of GA is improved
significantly at (GCE/Ag/Vulcan®) electrode compared with the unmodified electrode or even
(GCE/Vulcan®), in phosphate buffer. In acetate-acetic buffer it was demonstrated that the
sensitivity can duplicate on (GCE/Vulcan®) compared to the unmodified electrode. The new
modified electrodes were also tested on two white wines and one moscatel. It was found that
it is on (GCE/Vulcan®) and in phosphate buffer that wines differ most from each other.
Figure 1 – Cyclic voltammograms of
a glass carbon electrode (GCE) and
modified GCEs in 0.1 mM gallic acid
in phosphate buffer solution.
References
[1]- P. Kilmartin, H Zou, A Waterhouse, J. Agric. Food Chemistry, 49 (2001) 1957–1965.
[2]-, M. Aguirre, Y. Chen, M. Isaacs, B. Matsuhiro, L. Mendoza, S. Torres, Food Chemistry
121 (2010) 44–48.
[3]- M.J. Rebelo, R. Rego, M. Ferreira, M.C. Oliveira, Food Chemistry 141 (2013) 566–573.
Keywords: Polyphenols, gallic acid, antioxidant capacity, modified electrode, nanoparticles.
__ __ __ __ (GCE)
- - - - - - (GCE/Vulcan®)
___________ (GCE/Ag/Vulcan®)
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
34
P12
Modified electrodes for electrocatalysis: electropolimerisation based on
binuclear metal complexes
Sara Realista, Paulo Nuno Martinho, Ana Isabel Melato, Maria José Calhorda Departamento de Química e Bioquímica, CQB, Faculdade de Ciências, Universidade de
Lisboa, Campo Grande, 1749-016 Lisboa, Portugal, [email protected]
The development of modified electrodes with conducting polymers containing first
row transition metals has been a very active area of research in recent years, especially
because the metal centres are incorporated along the polymer backbone. Several applications
have been reported such as electrocatalysis, sensors and optical devices, among others [1]. A
common strategy for electrochemical synthesis of metal-containing polymers is to attach
polymerisable groups (aniline, pyrrole, etc.) onto metal complexes. Salphen-type polymers
are attractive, because extra synthetic steps can be avoided once Schiff base complexes can be
conveniently electropolymerised. Among monomers, bis(metallo)salphen are of special
interest for electropolymerisation. They behave as two connected independent salphen units
with possibility to fine tune each salphen with desirable properties. Synthesis of asymmetric
bis-salphen complexes permits the introduction of functional groups with different properties
and variation of the metal centres gives distinct redox behaviour. [2]
Here we present the synthesis of symmetric and asymmetric zinc(II), copper(II) and nickel(II)
bis-salphen complexes by reaction of 3,3’-diaminobenzidine with salicylaldehydes with
different substituents on the phenolate ring. The dinuclear complexes have been
electropolymerised on an inert substrate by potentiostatic and/or potentiodynamic modes and
their films characterized by cyclic voltammetry, atomic force microscopy and spectroscopic techniques.
1. P.H. Aubert, P. Aubert, M. Roche, P. Capedevielle, M. Maumy, G. Ricart, Chem. Mater.,
13, 2223 (2001)
2. M.F.S. Teixeira, Anal. Lett. 40, 1825 (2007)
Keywords: bis(metallo)salphen, electropolymerisation, redox behaviour, AFM Acknowledgments: We thank Fundação para Ciência e Tecnologia for financial support: PEst-OE/QUI/UI0612/2013.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
35
P13
Direct and catalyzed reduction of dissolved CO2 in aqueous media using a
polymeric gas diffusion membrane
Rui Gusmãoa,b
, Carlos Pereirac
aCentro de Química, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal
bInstituto de Polímeros e Compósitos/I3N, Universidade do Minho, Campus de Azurem, 4800-
058 Guimarães, Portugal cCentro de Investigação em Química, Faculdade de Ciências da Universidade do Porto,
4169-007 Porto, Portugal
Managing CO2 concentration is a crucial issue in aquaculture. The requirement for controlling
dissolved CO2 concentration, so that it is not too low for the nitrification processes and hence
for the quality of recirculated water, or too high, risking to induce negative effects in fish,
makes continuous, multipoint, dissolved CO2 monitoring a clear necessity. In general, the
aquaculture research associated costs for the gas-streaming infra-red techniques or fiber optic
sensors of dissolved CO2 are potentially prohibitive. Electrochemical sensors can be a cheaper
alternative for continuous, multipoint monitoring, thus contributing to the understanding of
water quality dynamics in hyperintensive aquaculture systems.
At a copper surface, the reduction of CO2 appears to be a multi-step and complex reaction
which involves shared intermediates and multiple reaction pathways. Although CO2 can be
electrochemically reduced directly on metal electrodes, either the potentials necessary are
exceedingly negative or the metal surface is rapidly poisoned by the adsorbed products or
intermediates. On the other hand, transition-metal molecular catalysts have proven to
efficiently and selectively reduce CO2 with moderate overpotentials and high Faradaic
efficiency.
In this study, we present the results of the electrochemical reduction of CO2 in aqueous media
making use of different polymeric gas diffusion membranes. Direct reduction was studied
using a Cu electrode and mediated reduction was performed either at carbon paste electrode
(CPE) or glassy carbon electrode (GCE) with Ni(cyclam) in solution.
Keywords: Carbon Dioxide, Electrochemical Reduction, Cu electrode, Ni(cyclam),
Polymeric Membrane.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
36
P14
Synthesis of lithium vanadium oxides nanoparticles by solution processing
for electrochromic devices
Santos, A.C.G, Pereira, L
Materials Science Department, CENIMAT-I3N and CEMOP-UNINOVA, FCT-UNL, Campus
de Caparica, 2829-516 Caparica, Portugal
Lithium-vanadium oxide nanoparticles were prepared by solution processing using the
reaction of an aqueous hydrogen peroxide solution with lithium and vanadium alkoxides,
LiO-n-C3H7 and VO(O-i-C3H7)3. The X-ray diffraction (XRD) studies confirmed that various
phases of the Li-V oxides, having the general formula of LixV2O5 (0≤x<2.2) were obtained at
a low temperature such ~300°C. A thin film was deposited and characterized by
electrochemical impedance spectroscopy, visible spectroscopy, TGA, DSC, and DRX and
tested as an ionic conductor in an electrochromic (EC) device with the following
configuration: substrate, electrode, electrolyte, electrochromic, counter-electrode, substrate.
Besides EC devices these materials also exhibit improved properties as reversible cathodes in
lithium batteries.
Keywords: lithium-vanadium oxides; solution processing; electrochromic.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
37
P15
Electrocatalytic properties of metalloporphyrins immobilized on platinum
nanoparticles stably linked to gold surfaces
I. Almeida, A. S. Viana
CQB, Departamento de Química e Bioquímica, Faculdade Ciências, Universidade de Lisboa,
Campo Grande 1749-016 Lisboa, Portugal
The catalytic performance of macrocyclic organometallic compounds, such as
metalloporphyrins, towards oxygen reduction reaction (ORR) has been widely studied since
they are relatively inexpensive and stable materials to be used as cathodes in fuel cells. Self-
assembled monolayers of metalloporphyrins containing Co and Fe, as central metal ions, and
different anchor groups (disulfides [1] or phosphonic acid [2]) were adsorbed on gold and
electrochemically activated graphite electrodes, respectively, promoting the ORR reaction [1,
2]. In order to improve the catalytic response of metalloporphyrins, nanoparticles may also be
covalently attached to the electrode surface to facilitate electron transfer between porphyrin
and electrode. Recently, we employed a simple one-step methodology to functionalize flat Au
(111) electrodes through reaction between carbon disulfide, gold nanoparticles and small
electroactive compounds (e.g. epinephrine, tryptophan) or enzymes (e.g. Glucose Oxidase),
which displayed biological activity after chemical immobilization [3].
The purpose of this work is to demonstrate the potential of carbon disulfide to
establish a stable linkage between platinum nanoparticles, modified with Co and Fe
porphyrins and vitamin B12 derivatives, and Au (111) surfaces. Surface modification was
carried out in two steps in ethanolic solution. The efficiency of this immobilization method is
confirmed by the electrochemical performance of the modified electrodes on the ORR
reaction in aqueous acidic medium. The presence of nanoparticles shifts the potential of ORR
towards more positive values, and generates higher current densities, regarding pure self-
assembled monolayers of the same derivatives. This approach using carbon disulfide is
compared to the well-known surface attachment of modified nanoparticles onto pre-formed
dithiol self-assembled monolayers. AFM imaging enabled to confirm nanoparticle
modification as well as their stable attachment to the gold electrodes.
Keywords: Metalloporphyrins, carbon disulfide, nanoparticles, electrocatalyis, oxygen
reduction reaction
[1] A. S. Viana, S. Leupold, F. -P. Montforts, L.M. Abrantes Electrochim. Acta 50 (2005)
2807
[2] J. Cabrita, A. S. Viana, L. M. Abrantes, Surface Science, 605 (2011) 1412
[3] I. Almeida, V. C. Ferreira, M. F. Montemor, L.M. Abrantes, A. S. Viana Electrochim.
Acta 83 (2012) 311
Acknowledgements: FCT for financial support: PhD scholarship - SFRH /BD/70673/2010
and PEst-OE/QUI/UI0612/2013
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
38
P16
Functionalization of iron oxide nanoparticles for biosensors
F. Henriquesa, M.D. Carvalho
a, A.S. Viana
b
aCCMM/Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de
Lisboa, Campo Grande, C8, 1749-016 Lisboa, Portugal, Tel: +351 21750000; Fax:
+351217500088; E-mail: [email protected] bCQB, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de
Lisboa, Campo Grande, C8, 1749-016 Lisboa, Portugal
In the last years, the interest on magnetic nanoparticles (MNPs) has been considerably
enhanced, especially due to a wide range of potential applications in biomedicine, but also in
other areas such as catalysis and biosensors. To this purpose, efficient and simple methods for
chemical modification of non-noble nanoparticles with target bio-compounds are necessary.
The in-situ formation and assemblage of dithiocarbamates on gold, with a bidentate N-C-S2
resonance structure, can be achieved through the one-pot reaction between carbon disulfide
and compounds containing amine groups, including biomolecules, and has been explored as
an alternative to thiolated self-assembled monolayers [1].
In this study, magnetite type nanoparticles with different mean sizes, and best described as
Fe3-xO4 [2], were immobilized on gold electrodes, using carbon disulfide, and their redox
behaviour was addressed by cyclic voltammetry. Using this approach, in the presence of
Laccase, known to catalyze the oxidation of phenolic compounds simultaneously with the
reduction of molecular oxygen to water, it was observed that this multi-copper enzyme could
be stably attached to the electrode. The biological activity of the Laccase modified
nanostructured electrode, was evaluated by cyclic voltammetry towards ABTS (2,2'-azino-
bis(3-ethylbenzothiazoline-6-sulphonic acid) in citrate phosphate buffer pH 4.5. Atomic force
microscopy imaging further confirmed surface modification by MNPs and also their
functionalization.
[1] I. Almeida, A. C. Cascalheira, A. S. Viana, Electrochimica Acta 55 (2010) 8686-8695
[2] M.D. Carvalho, F. Henriques, L.P. Ferreira, M. Godinho, M.M. Cruz, J. Solid State Chem.
201 (2013) 144-152
Keywords: Magnetic nanoparticles, carbon disulfide, biosensors interface, gold electrodes
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
39
P17
Electrocatalytic Properties of Self-assembled Monolayers of Porphyrins
and Chlorins Adsorbed from Phosphonic or
Carboxylic Acid Groups on ITO
J. F. Cabrita a,b
, L. M. Abrantes a, F. P Montforts
b, A. S. Viana
a a Centro de Química e Bioquímica, DQB, Faculdade de Ciências da Universidade de Lisboa,
Campo Grande, 1749-016 Lisboa, Portugal, Tel: +351 21 750 00 00, Fax: +351 21 750 00
88, E-mail: [email protected] bInstitut für Organische Chemie, FB 2 Biologie, Chemie der Universität Bremen, Postfach
330440, Bremen D-28334, Germany
Organophosphonic and carboxylic acid molecules have been used to form stable and
organized self-assembled monolayers (SAMs) on metal oxide substrates (e.g. ZnO [1] and
indium tin oxide (ITO) [2]), and also on noble metals (e.g Au [3]), with similar properties to
those of thiol/Au systems. When molecules with recognized catalytic activity are synthesized
with specific anchor groups, such as phosphonates or carboxylates, they can be assembled on
an electrode surface [4], enabling the study of their redox behavior in a large potential range.
In this work, the influence of different anchor moieties (–COOH e –PO3H2) of
porphyrins and chlorins on the monolayers formation onto ITO, from butanolic solutions, is
addressed. The redox properties of the modified electrodes were characterized by cyclic
voltammetry in organic medium, clearly showing the porphyrin and chlorin electrochemical
processes. UV-vis and infrared fourier transform diffuse reflectance spectroscopies and water
contact angle measurements corroborate the presence of the catalytic moieties and indicate
that phosphonic acid groups yield more organized monolayers with higher coverage than
those prepared from carboxylic acid. The electrocatalytic activity of the modified ITO
electrodes towards the reductive dehalogenation of lindane is assessed in organic medium,
and a reaction mechanism is proposed.
Acknowledgments
J. F. Cabrita acknowledges the PhD scholarship SFRH/BD/47703/2008 (Fundação para a
Ciência e Tecnologia) and PEst-OE/QUI/UI0612/2013.
References
[1] C.L. Perkins, J. Phys. Chem. C, 113 (2009) 18276.
[2] M. Chockalingam, N. Darwish, G. Le Saux, J. Justin Gooding, Langmuir, 27 (2011) 2545.
[3] J. F. Cabrita, A. S. Viana, F.-P. Montforts, L. M. Abrantes, Surface Science, 605 (2011)
1412.
[4] J. F. Cabrita, A. Viana, A. Mourato, L. M. Abrantes, Catalysis Today, 187 (2012) 70.
Keywords: self-assembled monolayers, phosphonic and carboxylic acid, porphyrins, chlorins,
lindane dehalogenation.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
40
P18
Smart’ coatings as sensors based on nanocontainers
Frederico Maia, Alexandre C. Bastos, João Tedim, Mikhail L. Zheludkevich and Mário G.S.
Ferreira
CICECO-Department of Materials and Ceramics Engineering, University of Aveiro, 3810-
193 Aveiro, Portugal
The increase in lifetime and conservation of intrinsic properties of metallic structures is one of
the biggest challenges currently faced by many industries.
Therefore, early detection (sensing) of substrate degradation could contribute to more cost-
effective maintenance planning and preventing occurrence of accidents with catastrophic
consequences.
One important class of materials being currently used to sense changes on the substrate or in
the surroundings is application of “smart” coatings with incorporated sensing active species
able to detect and respond to those alterations. The encapsulation/immobilization of active
compounds has the advantage of limiting undesirable interactions with coating matrix,
preventing the spontaneous leaching and imparting a controlled release and consequently
response to certain triggers.
In general, encapsulated species are incorporated into coatings and following external stimuli
which promote damage or other modification on the coating, the encapsulated species respond
according to their intrinsic characteristics (sensing). In the specific case of corrosion, there is
a pH change in the cathodic/anodic areas, where encapsulated pH indicators can be useful as
sensors [1]. In a broad sense detection of mechanical impacts in coatings can also be achieved
by encapsulation of dyes that are released or activated upon mechanical action leading to the
coloration of the coating.
In this work we report the encapsulation/immobilization of sensitive compounds in inorganic
nanocontainers [2] for incorporation in sensing coatings. These nanocontainers have the
ability to respond to certain triggers caused by corrosion or mechanical impacts, thereby
acting as sensors for specific structural applications.
References:
1. Frederico Maia, João Tedim, Alexandre C. Bastos, Mikhail L. Zheludkevich and Mário
G.S. Ferreira, “Nanocontainer-based corrosion sensing coating”, submitted.
2. Frederico Maia, João Tedim, Aleksey D. Lisenkov, Andrei N. Salak, Mikhail L.
Zheludkevich and Mário G.S. Ferreira, "Silica nanocontainers for active corrosion
protection", Nanoscale 4 (2012) 1287-1298.
Keywords: nanocontainers, nanoreactors, corrosion, sensing coatings.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
41
P19
Simultaneous Determination of Nickel and Cobalt, Using a Solid Bismuth
Vibrating Electrode, by Adsorptive Cathodic Stripping Voltammetry
Georgina M.S. Alves
a , Júlia M.C.S. Magalhães
a and Helena M.V.M. Soares
*a
aREQUIMTE, Departamento de Engenharia Química, Faculdade de Engenharia,
Universidade do Porto, Rua. Dr. Roberto Frias, 4200-465 Porto, Portugal *[email protected]
A simple, fast, sensitive and greener voltammetric procedure for simultaneous analysis
of nickel (Ni) and cobalt (Co) by square wave adsorptive cathodic stripping voltammetry
(SWAdCSV) using a solid bismuth vibrating electrode (SBiVE) was developed and is
presented for the first time [1]. The procedure enables to determine Ni together with Co, at
low concentration levels (gL-1
), in ammonia buffer 0.1 M (pH 9.2) and in the presence of
oxygen, and involves an adsorptive accumulation of metal-dimethylglyoxime (Ni-DMG and
Co-DMG) complexes on the electrode surface.
For Ni and Co, the detection limits, obtained with 30 s of accumulation time, were 0.6
and 1.0 gL-1
, respectively.
The method was free of metals (Cd, Cr3+
, Cr6+
, Cu, Fe and Pb up to 50 gL-1
, Al and
Mn up to 500 gL-1
; Zn up to 300 gL-1
) interferences up to the concentrations mentioned in
brackets.
The proposed method was validated for simultaneous determination of Ni and Co in
certified reference surface water and in river water samples with good results.
In conclusion, the analytical performance of the SBiVE proved to be comparable or
better than the bismuth film electrodes (BiFEs) with the advantage of allowing a faster and
simpler adsorptive methodology [it does not require the bismuth film formation (either ex-situ
or in-situ deposition), as well as the subsequent cleaning or activating procedures to
regenerate the electrode surface] than the ones previously described with BiFEs.
Keywords: Cobalt (Co), Nickel (Ni), Stripping voltammetry, Solid bismuth vibrating
electrode
ACKNOWLEDGMENTS
The authors thank to the "Fundação para a Ciência e a Tecnologia" (FCT) from Portuguese
Government for the financial support of this work with FEDER founds, by the Project PTDC/QUI-QUI/112439/2009. One of us (Georgina Alves) acknowledges a grant scholarship
(SFRH/BD/46521/2008) financed by FCT.
[1] Georgina M. S. Alves, Júlia M. C. S. Magalhães and Helena M. V. M. Soares,
Electroanalysis 25, 2013, 1247
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
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P20
The role of gold nanoparticles on the sensitivity of a bi-enzymatic biosensor
for carbamate pesticides determination
Thiago Mielle B.F. Oliveiraa,b
, Maria de Fátima Barrosoa, Simone Morais
a, Mariana Araújo
d,
Cristina Freired, Pedro de Lima-Neto
b, Adriana Nunes Correia
b, Maria B.P.P. Oliveira
c,
Cristina Delerue-Matosa*
aREQUIMTE, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto, Rua
Dr. Bernardino de Almeida 431, 4200-072 Porto, Portugal. *[email protected]; tel: +351
228340500; fax: +351 228321159. bGELCORR, Universidade Federal do Ceará, Fortaleza, Brasil
c REQUIMTE, Dep. Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua
de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal d REQUIMTE, Dep. de Química e Bioquímica, Faculdade de Ciências, Universidade do
Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
Chitosan (CS) is a natural polysaccharide with several electrochemical applications, including
in the development of biosensors. Below its pKa (6.5), it suffers a gelification process and
acts as an ideal microenvironment to electrodeposit several materials and biological elements,
due to the amino and hydroxyl groups distributed in its structure. However, because of its
insulating properties, it is necessary to enrich the polymeric matrix with conductor materials,
in order to overcome problems related to the charge-transfer resistance (Rct) and sensitivity of
the device. In this work, we developed a bi-enzymatic biosensor (LACC-TYR-AuNPs-
CS/GPE) for carbamate pesticides detection, based on graphene paste electrode (GPE)
modified by a hybrid film composed by CS, gold nanoparticles (AuNPs) and laccase (LACC)
and tyrosinase from (TYR). The experiments were carried out using 4-aminophenol (4-AMP)
as substrate in a Britton-Robinson (BR) buffer (pH 5.5). In the absence of enzymes, the
electrochemical behavior of 4-AMP is represented by a quasi-reversible process with well-
defined anodic (+0.31 V) and cathodic (+0.15 V) peaks. When pure CS was
electroimmobilized onto the GPE a decrease of the peak currents was observed due to the
insolating properties of this biopolymer. In the presence of AuNPs in the matrix (40%, v/v),
the current increased ca. 1.5 times, suggesting a better conductivity and sensitivity for
analytical applications. In the presence of LACC and TYR (2:1%, w/w), the oxidation process
of 4-AMP is catalyzed, generating a benzoquinone compound which is reduced at -0.07 V.
The results showed that in the absence of AuNPs this electrochemical signal was ca. 2 times
lower, proving the importance of the AuNPs in the biosensor configuration. The
corresponding Nyquist diagrams exhibited a large capacitive arc (Rct = 767 Ω) when pure C
was electrodeposited onto the GPE, indicating high charge-transfer resistance. Yet, when the
CS matrix was enriched with AuNPs, the charge-transfer resistance decreases sharply (Rtc =
407 Ω), corroborating the voltammetric findings. After the optimization of the square-wave
voltammetric parameters, the developed LACC-TYR-AuNPs-CS/GPE was applied to
determine trace concentrations of several carbamates in citrus fruits, with high precision and
low level of interferences.
Keywords: Chitosan; gold nanoparticles; polyphenoloxidases; bi-enzymatic biosensors;
carbamate pesticides.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
43
P21
Electrochemical properties of a gold nanoparticles doped organic/inorganic
hybrid matrix gel
Carlos J. R. Silva
a, Sandra D. F. C. Moreira
a,b, J. P. B Silva
b, Manuel F. M. Costa
b,
M. J. M. Gomesb
a Centre of Chemistry, University of Minho, Braga 4710-057, Portugal
b Centre of Physics, University of Minho, Braga 4710-057, Portugal
Sol-gel method is a commonly used synthesis procedure to obtain materials that are presently
relevant in large diversity of technological fields such as in optics, electronics, coatings, etc.
Besides, this simple preparative method allows a versatile combination of involved precursors
reagents with a large variety of substances and particles that could be embedded within the
gel network so the obtained materials with judicious mechanical, thermal, optical properties
and chemical structure and composition.
The so called organic-inorganic hybrid gels are characterized as networked materials where
the inorganic silicate backbones are bonded by polymeric chains giving to this materials a
background resistivity that could be changed by the kind of substances and particles that
could be dispersed within the two main components regions. These properties show to be
relevant for the development of materials for possible application in non-volatile organic
memory devices.
In this paper were characterized the electrochemical properties OIH gel, based on a amine-
alcohol-silicate (AA(600)) matrix where gold nanoparticles (AuNPs) with different diameters
(from 4 up to 10 nm) were immobilized. Besides the enhanced plasmonic properties, derived
from the size of the embedded nanoparticle, electrochemical impedance spectroscopy (EIS)
analysis revealed that AuNPs doped OIH gels low conductivity is dependent on dispersed Au
particle sizes. Complementary current–voltage (I–V) measurements confirms that these
materials show an electrical stable window of about 5 V range and the charge transfer
mechanism is strongly dependent on the potential applied across the OIH sample.
Keywords: Au nanoparticles, hybrid gels, electrochemical stability, sol-gel
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
44
P22
Immobilization of Metalloporphyrins onto Electrode Surfaces by
Electropolymerization of Tailored and Conventional Monomers
Isabel M. Ornelas a, Cláudia M. B. Neves
b, M. Graça P. M. S. Neves
b, Ana S. Viana
a, José
A. S. Cavaleiro b, Jorge P. Correia
a
aDepartment of Chemistry and Biochemistry & CQB, University of Lisbon, 1749-016 Lisbon,
Portugal; presenting author: [email protected] bDepartment of Chemistry & QOPNA, University of Aveiro, 3810-193 Aveiro, Portugal
The direct borohydride fuel cell (DBFC) presents a high theoretical specific energy [1] but, as
most of this type of energy converters, its kinetics is cathode-limited. Since it works in
alkaline conditions, the use of non-precious catalysts for oxygen reduction is allowed.
Nevertheless, platinum is still the most used material for this purpose due to its high activity
for the oxygen reduction reaction, high electrical conductivity and good stability, the high
cost being the main drawback for its commercial application [2]. N-containing conducting
polymers, such as polyaniline (PAni) and polypyrrole (PPy), also display interesting activities
for the electroreduction of O2 [3]; moreover, it has been shown that the metal-nitrogen sites in
“conducting polymer like” structures are very active for the molecular oxygen reduction [4],
justifying the good performance of metalloporphyrins for such reaction [5].
This work presents a systematic study of the electrode modification by the
electropolymerization of novel metalloporphyrins compounds specially functionalized with a
pendant aniline-type moiety. Thin polymer films were synthesized from organic media in the
presence or absence of free aniline, onto vitreous carbon and platinum supports. The polymer
deposition was accomplished potentiodynamically and potentiostatically, and monitored by
microgravimetry. The morphology of the polymers was accessed by atomic force microscopy.
References:
1 - U.B. Demirci, J. Power Sources 169 (2007) 239.
2 - H. Chen, K. Scott, K. Lovell, Fuel Cells 6 (2006) 367.
3 - V.G. Khomenko, V.Z. Barzukov, A.Katashinskii, Electrochim. Acta 50 (2005) 1675.
4 – R. Bashyam, P. Zelenay, Nature 443 (2006) 63.
5 – H. Tang, H. Yin, J. Wang, N. Yang, D. Wang, Z. Tang, Angewandte Chemie 52 (2013)
5585.
Keywords: Oxygen reduction, Metalloporphyrins, Conducting polymers, DBFC.
Acknowledgements:
Fundação para a Ciência e a Tecnologia (project PTDC/QUI-QUI/121857/2010 and PEst-
OE/QUI/UI0612/2013). Thanks are also due to the University of Aveiro, ‘Fundação para a
Ciência e a Tecnologia’ (FCT) and F D R for funding the QOPNA Unit. We thank the
Portuguese National NMR network supported by funds from FCT.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
45
P23
Influence of Zeolite Particles and Inhibitor as Additive for Concrete in the
Rebar Corrosion Protection
C. Vicentea,A. S. Castela
a,b, R. Neves
a, M. F. Montemor
b
aInstituto Politécnico de Setubal, ESTBarreiro, 2389-001 Barreiro, Portugal
bICEMS, Instituto Superior Técnico, Technical University of Lisbon, 1049-001, Lisboa,
Portugal
The main goal of this work was to study the influence of past additives in reinforced concrete
steel samples relatively to stability and protective behavior of the concrete and rebar corrosion
resistance. The additives used were the followings: SIKA Ferrogard 901 commercial inhibitor
containing anti-corrosion molecules, such as alkanolamines (AMAs), and spent zeolites
catalysts from FCC units (Fluid Catalytic Cracking, petrochemical industry). The
water/cement ratio used was 0.6 and a plasticizer was added to the past.
The main technique used to study the samples was Electrochemical Impedance Spectroscopy
(EIS). Reinforced concrete steel samples were constituted by a graphite rod embedded in the
samples, which was used as a reference electrode, while four steel rods also embedded were
used to simulate a rebar and as working electrodes and counter-electrode. Measurements were
performed in a three-electrode arrangement. The frequency range used was 100KHz to 5mHz
with a 10mV amplitude. The samples were kept in a dry/immersion cycles for longer periods
and measurements were regular carryout during all the process. A saturated NaCl immersion
solution was used.
Beneficial influence in the properties of concrete by zeolites or by a synergic effect with the
inhibitor seems evident, with a favorable influence in the protection of the rebar, increasing
the time for the beginning of corrosion which improves the durability of the reinforced
concrete steel samples.
Keywords: concrete; reinforced concrete steel, zeolites; corrosion inhibitor, EIS.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
46
P24
New phenolic imidazole derivatives: evaluation of antioxidant activity
A.P. Bettencourt, F. Lobo, A.C. Leite, C. Correia, M.A. Carvalho, M.F. Proença
Departamento de Química, Universidade do Minho, Campus de Gualtar,
4710-057 Braga, Portugal
The damage caused by free radicals, namely reactive oxygen species (ROS), in biological
systems has been extensively studied over the last few decades. The development of several
diseases, mainly those affecting the central nervous system such as Alzheimer’s disease,
Parkinson’s disease and some tumours, are associated to oxidative stress [1-4]
. Efforts to solve
this problem mainly focus on the use of substances that can act as scavengers of free radicals,
acting as antioxidants [1-4]
. Therefore, there has been a growing interest in the synthesis and
development of novel compounds that can act as antioxidants. It is also essential to have a
simple, fast and reliable method to measure the antioxidant activity of new compounds and
several chemical and electrochemical methods have been developed for this purpose [5,6]
.
In this work a series of new phenolic imidazole derivatives was synthesized and the
antioxidant activity of all the compounds was evaluated by cyclic voltammetry. The effect of
the nature of the substituents on N1 of the imidazole ring and the number and position of
hydroxyl groups of the phenolic subunit on the oxidation peak potentials of the phenolic
imidazole derivatives was evaluated. Antioxidant activity data obtained from anodic peak
potential measurements were correlated to the ones gotten by the DPPH radical and deoxy-D-
ribose degradation assays.
Acknowledgments: To FCT and FEDER-COMPETE-QREN-EU for financial support to the
Research Centre, CQ/UM [PEst-C/QUI/UI0686/2011 (FCOMP-01-0124-FEDER-022716)].
[1] A. Contestabile, Curr. Top. Med. Chem. 2001, 1, 553.
[2] C. A. Collins, F. H. Fry, A. L. Holme, A. Yiakouvaki, A. Al-Qenaei, C. Pourzand, C.
Jacob, Org . Biomol. Chem. 2005, 3, 1541.
[3] B. Halliwell, Drugs and Aging, 2001, 18, 685.
[4] J. G. Fernández-Bolaños, Ó. López, J. Fernández-Bolaños, G. Rodríguez- Gutiérrez, Curr.
Org. Chem., 2008, 12, 442.
[5] L.M. Magalhães, M. A. Segundo, S.Reis, J. L.F.C. Lima, Anal. Chim. Acta, 2008, 613, 1.
[6] A. J. Blasco, A. G. Crevillén, M. C. González, A. Escarpa, Electroanalysis, 2007,19,
2275.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
47
P25
Gold nanoparticles-based biosensor for determination of amyloid
beta-peptide
P. Carneiroa,b
, J.A. Loureiro, S.C. Coelho, C. Delerue-Matosb, S. Morais
b, M.C. Pereira
a
a LEPAE, Department of Chemical Engineering Faculty of Engineering, University of Porto,
Portugal. b REQUIMTE, Instituto Superior de Engenharia do Porto, Instituto Politécnico do Porto,
Portugal. [email protected]; tel: +351 228340500; fax: +351 228321159
Alzheimer disease (AD) is a neurodegenerative pathology characterized by extracellular
deposits of amyloid β (Aβ) peptide (senile plaques). ince this disease is very difficult to
diagnose, it is clinically important to find and detect accurately biomarkers for AD by new
non-invasive methods that may facilitate the diagnostic process and identify patients at an
earlier stage [1]. Thus, the aim of the proposed research was to develop a sensitive gold
nanoparticles-based immunosensor for the detection of the main AD biomarker, i.e, amyloid
beta-peptide, in biological fluids.
Cyclic voltammetry, square-wave voltammetry and electrochemical impedance spectroscopy
were selected for the biosensor characterization. The proposed immunosensor was
constructed in four steps: 1) formation of a self-assembled monolayer (SAM); 2)
electrodeposition of gold nanoparticles (AuNPs); 3) antibody immobilization; 4) analysis of
the signal resulting from the antibody-antigen interaction.
Firstly, several SAMs and experimental conditions were tested, namely, cystamine,
cystamine+mercaptoethanol, mercaptopropionic acid and mercaptopropionic
acid+mercaptoethanol at different concentrations and immersion times. The best results were
attained using 5 mmol/L mercaptopropionic acid and a time of immersion of 2 h.
Concerning the synthesis of AuNPs, the Turkevich method was used. Hydrodynamic size and
potential zeta values were characterized by dynamic light scattering and laser doppler
velocimetry, respectively. AuNPs exhibited a 37 nm mean hydrodynamic diameter and a -38
mV zeta potential. Electrochemical deposition of the AuNPs on the previously SAM modified
electrode was carried out at - 0.2 V for 500 s.
For the antibody immobilization, several concentrations and incubation times were evaluated.
The antibody was functionalized in order to support its correct orientation, with minimal
steric hindrance to interact favorably with its target antigen. The best results were obtained
using a 1 µg/mL concentration of antibody and an incubation time of 7.5 h. The antibody-
antigen interaction was firstly characterized using an ELISA test in order to estimate the
necessary time (5 min.) to promote the reaction between the antibody and the antigen. The
developed gold nanoparticles-based immunosensor allows accurate and reproducible
detection of the amyloid-beta peptide at low levels.
Acknowledgements: This work was supported by project PTDC/QUI-BIQ/102827/2008. [1] Hampel, H., Shen, Y., Walsh, D., Aisen, P., Shaw, L., Zetterburg, H., Trojanowski, J. and Blennow, K. (2010), Experimental Neurology, 223, 334-346.
Keywords: Alzheimer’s disease; Amyloid-beta peptide; Immunosensor; Gold nanoparticles;
Self-assembled monolayer.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
48
P26
Application of a DNA-based biosensor for the electrochemical investigation
of the effect of free radicals and antioxidants
Sofia Costaa, Diana Cruz
a, M. Fátima Barroso
a, M. J. Ramalhosa
a, Abel J. Duarte
a, C.
Delerue-Matosa
aREQUIMTE, Instituto Superior de Engenharia do Porto, Rua Dr. António Bernardino de
Almeida, 431, 4200-072 Porto, Portugal
Reactive oxygen and nitrogen species (ROS and RNOS) such as hydrogen peroxide (H2O2),
hydroxyl radical (HO·) and nitric oxide (
·NO) are formed in vivo during aerobic metabolism.
Although cells have developed various enzymatic and nonenzymatic systems to control ROS
and RNOS production, a certain fraction escapes the cellular defense and may cause
permanent or transient damage to proteins, lipids, and nucleic acids (1).
Some food and beverage compounds have an important external contribution to body
defenses against oxidative insult. It provides cell specific antioxidants that are able to
scavenge multiple types of free radicals contributing to maintain cellular health.
In this work, an electrochemical DNA-based biosensor was developed in order to assess the
total antioxidant capacity (TAC) of foodstuffs.
The performance of this biosensor consisted in four steps: i) deoxyadenylic acid
oligonucleotide (dA) immobilization onto carbon paste electrodes (CPE); ii) Damage of the
dA by the immersion of the bioelectrode on the free radicals (H2O2, HO· and
·NO) iii)
Protective effect promoted by antioxidants, in the presence of free radicals, onto de dA-CPE
iv) Detection and measurement of the oxidation peak current of the dA using square wave
voltammetry (SWV).
References
(1) Richter, C., Park, J-W., Ames, B.N. (1988) Proc. Nati. Acad. Sci. 85, 6465-6467.
Acknowledgments
M.F. Barroso is grateful for the post-doc fellowship (SFRH/BPD/78845/2011) financed by
POPH–QREN–Tipologia 4.1–Formação Avançada, subsidized by Fundo Social Europeu and
Ministério da Ciência, Tecnologia e Ensino Superior. This work has been supported by FCT
through grant no. PEst-C/EQB/LA0006/2011 and project PP-IJUP-2011-276.
Keywords: DNA; free radicals, antioxidants; biosensors.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
49
P27
Study of electrochemical properties of a protective film formed onto nickel
when immersed in alkali metal solutions
Cilene Vicentea, R. G. Duarte
a,b, A. S. Castela
a,b
aInstituto Politécnico de Setubal, ESTBarreiro, 2389-001 Barreiro, Portugal
bICEMS, Instituto Superior Técnico, Technical University of Lisbon, 1049-001, Lisboa,
Portugal
Nickel and nickel alloys are important materials for the design of vessels in different process
industries. Nickel electrode is also used in different energy-producing cells in which aqueous
or no aqueous solutions are used as electrolytes. Nickel and its alloys exhibit excellent
corrosion resistance in aqueous aggressive environments, which are attributed to the ability of
nickel to form a stable passive film on its surface [1].
The nature and the mechanism of formation of the passive film depend, among other factors,
on the composition and pH of the electrolyte. In alkaline environments, NiO was proved to be
the main constituent of the passive film on Ni surface [2]. Passivity is a crucial factor in
determining the capability of metals to resist corrosion. Investigation of the electrochemistry
of a passivity metal can reveal not only the structure and composition, but also the corrosion
behavior of the film [3].
The corrosion resistance was investigated by electrochemical techniques, specifically
electrochemical impedance spectroscopy (EIS) and polarization curves. The frequency range
used was from 100 KHz to 5 mHz and were 7.13 reading per decade of frequency. The
impedance results were treated using the software ZView. The polarization curves were
obtained in the range -0.5 to 1.0 V at scan rate of 10 mV/s. The equipment used the G-300
Gamry Instruments. Several alkaline halide solutions were used and Chemical
characterization of the films was performed by SEM. Influence of the electrolyte composition
in passive film properties were detected.
Keywords: EIS; nickel; passive film; alkaline metal solutions
Reference
1. Abd El Aal, E.E., Breakdown of passive film on nickel in borate solutions containing
halide anions. Corrosion Science, 2003. 45(4): p. 759-775.
2. Abd El-Haleem, S.M. and S. Abd El-Wanees, Chloride induced pitting corrosion of
nickel in alkaline solutions and its inhibition by organic amines. Materials Chemistry
and Physics, 2011. 128(3): p. 418-426.
3. Guiñón-Pina, V., A. Igual-Muñoz, and J. García-Antón, Influence of temperature and
applied potential on the electrochemical behaviour of nickel in LiBr solutions by
means of electrochemical impedance spectroscopy. Corrosion Science, 2009. 51(10):
p. 2406-2415.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
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P28
Development of an electrochemical aptasensor for protein detection
Sofia G. Meirinhoa, Luís Dias
b, Antonio M. Peres
b, Lígia R. Rodrigues
a
aCentre of biological Engineering, University of Minho
bLaboratory of Separation and Reaction Engineering, Escola Superior Agrária, Polytechnic
Institute of Bragança
The development of aptamer-based electrochemical biosensors as an emerging technology has
made the detection of small and macromolecular analytes easier, faster, and more suited for
early detection of protein biomarkers. Biomarkers are produced by body organs or tumors and
measure antigens on cell surfaces. When detected in high amounts in blood, they can be
suggestive of tumor activity 1,2
. These markers are more often used to evaluate treatment
effects or to assess the potential for metastatic disease in patients with established disease.
Osteopontin (OPN) is a protein found in all body fluids, and constitutes a possible biomarker
because its overexpression has been related with breast cancer evolution and metastasis 3–5
.
Currently, biomarkers are commonly used for the development of diagnostic methods,
allowing the detection of the disease in its initial stages. An electrochemical aptasensor for the
detection of OPN was developed using an RNA aptamer immobilized on a gold screen-
printed electrode (Au/SPE). The immobilized biotin-modified aptamer on Au/SPE constitutes
the biorecognition element for the target protein and the electrochemical signal generated
from the interaction aptamer-target protein was evaluated by cyclic voltammetry (CV). A
decrease in the current as a consequence of protein binding to the aptamer was observed
through the analysis of the electron flow produced by a redox reaction between ferri- and
ferrocyanide. The electrochemical aptasensor herein developed presents a high specificity for
OPN as compared with other proteins commonly found in the biological fluids.
Keywords: Osteopontin; aptamer; aptasensor; screen-printed electrode; cyclic voltammetry
Acknowledgment: This work was financially supported by Fundação para a Ciência e a
Tecnologia (FCT) through the PhD grant SRFH/ BD/65021/2009.
Reference: 1. Karley, D., Grupta, D. & Tiwari, A. Biomarkers: The Future of Medical Science to Detect
Cancer. Journal of Molecular Biomarkers & Diagnosis 2, 2–5 (2011).
2. Rodrigues, L. R., Teixeira, J. A., Schmitt, F. L., Paulsson, M. & Lindmark-Mansson, H.
The Role of Osteopontin in Tumor Progression and Metastasis in Breast Cancer. Cancer
Epidemiology, Biomarkers & Prevention 16, 1087–1097 (2007).
3. Rodrigues, L. R., Lopes, N., Sousa, B., Vieira, D. & Milanezi, F. Significance of
Osteopontin Expression in Human Invasive Breast Tumour Stroma. The Open Breast Cancer
Journal 1, 1–9 (2009).
4. Macrì, A. et al. Role of osteopontin in breast cancer patients. Tumori 95, 48–52 (2009).
5. Ahmed, M. & Kundu, G. C. Osteopontin selectively regulates p70S6K / mTOR
phosphorylation leading to NF-κB dependent AP-1-mediated ICAM-1 expression in breast cancer
cells. Molecular Cancer 9, 1–13 (2010).
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
51
P29
Modified Titanate Nanotubes Decorated with Nanocrystalline Bi2S3 as New
Materials for Sensor Applications
J. F. Cabrita a, O. C. Monteiro
a a Centro de Química e Bioquímica, DQB, Faculdade de Ciências da Universidade de Lisboa,
Campo Grande, 1749-016 Lisboa, Portugal, Tel: +351 21 750 00 00,
Fax: +351 21 750 00 88, E-mail: [email protected]
Nanostructured materials have become one of the most important research subjects
and have established a remarkable development in a wide assortment of scientific fields [1].
Despite all known successes, the control of the materials’ intrinsic properties is still difficult
and challenging. The synthesis of nanocomposite materials has been one of the most fruitful
methods for solving this issue: by synergetically combining several materials it is possible to
prepare new materials with improved and innovated properties [2,3].
Titanate nanotubes (TNTs) combining the properties of conventional TiO2
nanoparticles with the properties of layered titanates, have received increasing attention
because of their wide potential applications, including sensor [4]. The open mesoporous
morphology together with the absence of micropores and the high specific surface area should
facilitate transport of reagents during the process. Simultaneously, for the nanoscale coupled
semiconductors it can be expected that the TNTs electro-activity will be significantly
improved by the enhancement of charge separation and minimization or inhibition of charge-
carrier recombination. The synthesis of TNTs and posterior sensitization with Bi2S3
nanocrystalline semiconductor particles was investigated in this work. The TNTs and
Bi2S3/TNTs nanocomposite powders were prepared and characterized, by TEM, SAED, SEM,
DRX and DRS. The evaluation of the electrochemical properties of Bi2S3/TNTs
nanocomposites were carefully analyzed and their performance attested for the ascorbic acid
electrocatalytic oxidation.
Acknowledgments
This work was financially supported by FCT under the projects
PTDC/CTM/NAN/113021/2009 and PEst-OE/QUI/UI0612/2013.
References
[1] D.V. Bavykin, F.C. Walsh, “Titanate and titania nanotubes: synthesis, properties and
applications”, R C, Cambridge, 2010.
[2] E.K. Ylhainen, M.R. Nunes, A.J. Silvestre, O.C. Monteiro, J. Mater. Sci. 47 (2012) 4305.
[3] V. Bem, M.C. Neves, M.R. Nunes, A.J. Silvestre, O.C. Monteiro, J. Photochem.
Photobiol. A 232 (2012) 50.
[4] Y.P. Dong, L. Huang, J. Zhang, X.F. Chu, Q.F. Zhang, Electrochimica Acta, 74 (2012)
189.
Keywords: Nanostructured materials, titanate nanotubes, nanocrystalline Bi2S3, ascorbic acid,
electrocatalysis.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
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P30
Disposable immunosensor with simple antibody orientation for label-free
real-time detection of a cancer biomarker
Nádia S. Ferreira, M. Goreti F. Sales
BioMark/ISEP, School of Engineering, Polytechnic Institute of Porto, R. Dr. António
Bernardino de Almeida, 431, 4200-072, Portugal. Tel: +351228340544;
E-mail: [email protected]; [email protected]
Oxidative Stress is the imbalance between oxidant-producing systems and antioxidant defense
mechanisms, resulting in an excessive production of reactive oxygen species. This condition
is widely recognized as a central feature of many biological processes and diseases, such as
cancer. The oxidized nucleotide 8-hydroxy-2’-deoxyguanosine (8OHdG) is among the several
indicators used for screening oxidative cell damage. The methods presently used to quantify
this biomarker involve complex, expensive and non-portable techniques.
As an alternative, this work reports a novel immunosensor for this purpose. It was assembled
by employing a novel strategy for suitable antibody orientation, aiming its subsequent
application in the determination of 8OHdG in point-of-care. The Anti-8OHdG was bound to
an amine modified gold support through its Fc region, by effective covalent binding to the
carboxylic function. Non-oriented approaches of antibody binding to the platform were tested
in parallel, in order to show that the presented proposal favored antibody/antigen affinity.
The immunosensor design was evaluated by Quartz-Crystal microbalance with Dissipation,
Atomic Force Microscopy, Electrochemical Impedance Spectroscopy (EIS) and Square-Wave
Voltammetry. EIS was also a suitable technique to follow the analytical behavior of the
device against 8OHdG. The affinity binding between 8OHdG and the antibody immobilized
in the gold modified platform increased the charged transfer resistance across the
electrochemical sep-up. The observed behavior was linear from 0.02 to 7.0 ng/mL 8OHdG.
Interference from Glucose, Urea and Creatinine was found negligible. An attempt of
application to synthetic samples was also successfully conducted.
Overall, the presented approach enabled the production of suitably oriented antibodies over a
gold platform by means of a much simpler process than other oriented-antibody binding
approaches described in the literature, as far as we know, and was successful in terms of
analytical features and sample application.
Keywords: Immunosensor; Oriented antibody binding; Cancer biomarker; 8-hydroxy-2’-
deoxyguanosine.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
53
P31
Smart Plastic Antibody Material for Hemoglobin Tailored by Silica Surface
Imprinting and with Charged Binding Sites: Its use as Ionophore in
Potentiometric Transduction
Ana P. T. Moreira, Felismina T.C. Moreira, M. Goreti F. Sales
BioMark/ISEP, School of Engineering, Polytechnic Institute of Porto, R. Dr. António
Bernardino de Almeida, 431, 4200-072, Portugal. Tel: +351228340544;
E-mail: [email protected] ; [email protected]
Human hemoglobin (Hb) is a globular metalloprotein, present in the blood and involved in
gas transport. Hb-associated disturbances are related to several diseases, such thalassemia,
anemia, heart disease and leukemia, or to side-effects from other diseases, such as cancer.
Overall, it is of great importance to know the concentration of Hb in the blood in many
health-related conditions.
There are many methods described in the literature for determining Hb. Most of these rely on
antibody/antigen interactions, due to the high selectivity of the affinity reaction taking place
between these biomolecules. However, the use of antibodies for Hb determination in routine
clinical use is very expensive, due to the high cost of the material, the need for special
handling and storage, and the non-reusability. These constraints may be limited by replacing
natural antibodies by plastic receptors, obtained by molecular imprinting procedures.
Thus, this work describes a novel smart plastic antibody material (SPAM) by surface
imprinting technique for the detection of Hb and its application to design small, portable and
low cost potentiometric devices. The SPAM material was obtained by linking Hb to silica
nanoparticles and allowing its subsequent interaction with different vinyl monomers, of
different chemical functions and ionic charges. Control materials were designed in parallel to
assess the ability of establishing stereochemical recognition of Hb and the effect of the
kind/charge of the monomers employed. Scanning Electron Microscopy analysis confirmed
the surface modification of the silica material used for imprint.
All materials were mixed with PVC/plasticizer and applied as selective membranes in
potentiometric transduction. Suitable emf variations were detected only for selective
membranes having a SPAM material and a charged lipophilic anionic additive. All control
materials were unable to produce a potentiometric response.
Overall, good features were obtained for SPAM-based selective membranes carrying an
anionic lipophilic additive. In H P buffer of pH 5, limits of detection were 43.8μg/mL for
a linear response after 83.8μg/mL with a cationic slope of +40.4mV/decade. Good selectivity
was also observed against other coexisting biomolecules. The analytical application was
conducted successfully, showing accurate and precise results.
Keywords: Surface molecular imprint; Hemoglobin; Potentiometry; Ion-selective electrodes.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
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P32
Carnitine tailored Sensors on Surface Molecular Imprinting based on
Graphene layers
Liliana A.A.N.A. Truta, Nádia S. Ferreira, M. Goreti F. Sales
BioMark/ISEP, School of Engineering, Polytechnic Institute of Porto, R. Dr. António
Bernardino de Almeida, 431, 4200-072, Portugal. Tel: +351228340544;
E-mail: [email protected]; [email protected]
A new biosensor based on surface molecularly imprinted polymer (MIP) on graphene layers
was successfully developed. It consists in a 3D polymeric network created on top of surface
and around the target template, Carnitine (CRT), a potential biomarker of ovary cancer. The
polymeric structure was obtained after radical polymerization of
(vinylbenzyl)trimethylammonium chloride, 4-styrenesulfonic acid and vinyl pivalate,
including in the reaction mixture ethylene glycol dimethacrylate as cross-linker and
ammonium persulphate as initiator. Non-imprinted polymer (NIP) material was also
produced, by excluding the template from the procedure.
The imprinted graphene structures were further used for the selective determination of CRT
by potentiometric transduction. For this purpose, a selective membrane was prepared by using
the MIP material as ionophore, and dispersing it in a plasticized poly(vinylchloride) matrix,
that included (or not) a suitable amount of charged lipophilic additive. The membranes were
casted over a solid conductive support, made of graphite or of conductive glass. Control
membranes were also produced by replacing MIP by NIP material.
The potentiometric performance of the above electrodes was assessed against CRT solutions
of increasing concentrations. Graphite supports displayed the best analytical features, with
average slope and detection limit of 40.51 mVdecade-1
and 3.55x10-6
molL-1
, respectively.
The effect of pH upon the potentiometric response was evaluated for different buffer solutions
(within 2-9) and the best performance for this sensor was obtained with HEPES (4-(2-
hydroxyethyl)-1-piperazineethanesulfonic acid) buffer of pH 5.2. The interference effect of
albumin, ascorbic acid, glucose, creatinine and urea in the performance of the electrochemical
unit was tested for concentrations up to their normal physiologic levels in urine and good
selectivity was observed. The application of the devices to the analysis of spiked samples
showed recoveries ranging from 91% (± 6.8%) to 118% (± 11.2%), with relative errors below
-20%.
Overall, the combination of the MIP sensory material with a suitable selective membrane and
electrode design showed to be a promising tool for point-of-care applications.
Keywords: Carnitine; Surface Molecularly imprinted sensors; Graphene; Solid conductive
supports; Potentiometry.
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P33
A Biomimetic Biosensor based on Poly(o-aminophenol) film for Cardiac
Biomarker detection in Point-of-Care
Felismina T.C. Moreiraa,b,c
, Sanjiv Sharmad, Rosa A. F. Dutra
e, João P. C. Noronha
c, Anthony
E. G. Cassd, M. Goreti F. Sales
a
aBioMark/ISEP, School of Engineering, Polytechnic Institute of Porto, R. Dr. António
Bernardino de Almeida, 431, 4200-072, Portuga. Tel: +351228340544; Email:
[email protected] bINESC-TEC (coordinated by INESC Porto), Faculdade de Ciências da Universidade do
Porto, Rua do Campo Alegre, Porto, Portugal. cREQUIMTE/FCT-UNL, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa,
2829-516 Caparica, Portugal. dDepartment of Chemistry & Institute of Biomedical Engineering, Imperial College, London,
UK. ePROCAPE, LAPED, Universidade Federal de Pernambuco, Recife, Brazil.
Acute coronary syndrome (ACS) is a spectrum of acute myocardial ischemia spanning from
unstable angina to acute myocardial infarction (AMI). Patients under AMI require from
emergency medical assistance a quick diagnosis, but symptoms of chest pain, pressure,
shortness of breath, and/or nausea are common to acute myocardial ischemia conditions.
Myoglobin (Myo) is a nonspecific biomarker that appears in the peripheral circulation as
early as 1 to 2 hours after cardiac damage. Quick and low-cost methods for Myo
detection/determination in point-of-care are therefore appreciated.
This work describes for this purpose an electropolymerized molecular imprinting (EMI)
polymer film for Myo detection in ischemic episodes. The EMI is composed with Myo and
aminophenol (AP) monomer deposited on gold screen printed electrode surface (Au-SPE).
Myo was removed from the polymeric matrix was with proteinase K. A non-imprinted
material (NI) was synthesized by following the same procedure without having a template.
This material was used as a negative control. Atomic Force Microscopy and RAMAN
Spectroscopy analysis confirmed the surface modification of the working area in the Au-SPE.
The ability of the biomaterial EMI and its negative control NI to rebind Myo on the Au-SPE
support was followed electrochemically. Electrochemical Impedance Spectroscopy (EIS) and
Square Wave Voltammetry (SWV) were used for this purpose. The NI/Au-SPE was unable to
interact with Myo in a predicted way, showing a similar-to-random behavior. EMI/Au-SPE
devices displayed an opposite behavior, showing linear responses to Myo down to 3.5 g/mL
or 0.58 g/mL in EIS or SWV assays, respectively. The corresponding detection limits were
1.5 µg/mL or 0.28 µg/mL. EMI also showed negligible interference from troponin T, bovine
serum albumin and urea under SWV assays, showing promising results for point-of-care
applications when applied to spiked biological fluids.
Keywords: Myoglobin; Screen-Printed Electrodes; Molecular Imprinting; Electro
polymerization.
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P34
Organic-Inorganic Hybrid Sol-gel Coatings to Prevent Corrosion of
Galvanized Reinforcing Steel
R. B. Figueiraa, E. V. Pereira
a, C. J. R. Silva
b, M. M. Salta
a
aLNEC – Laboratório Nacional de Engenharia Civil,
Av. do Brasil 101, 1700-066 Lisboa, Portugal,
bCentro de Química, Universidade do Minho, Braga, Portugal.
The use of hot dip galvanized steel (HDGS) has been recognized as one effective measure to
increase the service life of reinforced concrete structures exposed to carbonation or to
chlorides ions. Immediately after concreting, with the hydration of the fresh concrete,
passivating surface layers made of calcium hydroxyzincate are formed, consuming between 5
and 10 µm of zinc. Simultaneous hydrogen evolution may also develop, leading to the loss of
adherence between steel and concrete [1].
This work describes the studies developed for applying a sol-gel method to produce organic-
inorganic hybrid (OIH) coatings over HDGS and evaluates their efficiency as a pretreatment
to reduce the formation of excessive amounts of zinc oxides as well as H2 evolution. OIH
matrices were synthesized by using a functionalized metal alkoxide as precursor (3-
isocyanatopropyltriethoxysilane) that was made to react with five oligopolymers (Jeffamines)
with different molecular weight in a 2:1 molar ratio. The inclusion of Cr(III) as corrosion
inhibitor within the OIH coating was also tested [2]. All coatings were produced over HDGS
samples by dip-coating method.
OIH coatings performance was evaluated by electrochemical and surface analysis techniques
(SEM/EDS and GD-OES). For electrochemical studies, galvanic current and polarization
resistance measurements were performed over a 70 days period in electrochemical cells
specially designed to be embedded in cement based materials.
It was concluded that, when compared non-coated HDGS samples, all the OIH sol-gel
coatings produced reduce the corrosion activity during the initial stages of contact of the
HDGS with the high alkaline environment of the cement based materials studied.
Furthermore, all the hybrid sol-gel coatings allowed the formation of calcium hydroxyzincate
corrosion protective layers on the surface of the steel.
Keywords: Organic-inorganic Hybrids, Sol-gel, Galvanized Steel, Corrosion.
[1] Yeomans, S. R., Galvanized steel reinforcement in Concrete, Elsevier: Amsterdam, 2004,
chapter 1.
[2] R. B. Figueira, C.J.R. Silva, E.V. Pereira, M. M. Salta, Proceedings from Electrochemistry
2012 - Fundamental and Engineering Needs for Sustainable Development, München,
September 17 – 19th.
[3] R. B. Figueira, E. V. Pereira, C. J. R. Silva,
M. M. Salta, Proceedings from XVIII Meeting
of the Portuguese Electrochemical Society, Porto, 24th-27
th of March 2013.
Acknowledgements: The authors thanks the FCT for research the PhD grant
SFRH/BD/62601/2009 and the financial support by Centro de Química [project F-COMP-01-
0124-FEDER-022716 (ref. FCT Pest-C/Qui/UI0686/2011)-FEDER-COMPETE].
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P35
Characterization of ZnO Nanoparticles on Electrode Surfaces by
Electrochemical Techniques
José A. Ribeiro, Paula M.V. Fernandes, Carlos M. Pereira*, Fernando Silva
Faculdade de Ciências da Universidade do Porto, Departamento de Química e Bioquímica,
Centro de Investigação em Química – Linha 4
Rua do Campo Alegre 687 – 4169-007 Porto – Portugal
ZnO nanostructures have a wide range of high technology applications such as surface
acoustic wave filters, photonic crystals, photodetectors, light emitting diodes, photodiodes,
gas sensors, optical modulator waveguides, solar cells and varistors [1]. ZnO nanoparticles
are also receiving a lot of attention because of its antibacterial property and its bactericidal
efficacy has been reported to increase as the particle size decreases [2].
The synthesis and characterization of nanoparticles are two essential aspects to any study
given that their reactivity and properties are defined by their composition, size and
morphology. Scanning electron microscopy (SEM), transmission electron microscopy (TEM),
atomic force microscopy (AFM), scanning tunnelling microscopy (STM) and X-ray
diffraction (XRD) are usually employed for the characterization of nanoparticles [3].
However, these techniques have some limitations which are particularly unfavourable when
examining nanoparticle-modified electrodes. Thus, the inefficiency in cost and time and the
sample preparation restrictions prevent the analysis of modified electrodes immediately
before or after each experiment [3].
The aim of this work is to provide a simple and time-efficient in situ characterization method
for ZnO nanoparticles on electrode surfaces using electrochemical techniques. The approach
proposed is based on routine electrochemical experiments.
Keywords: ZnO, Nanoparticles, Electrochemical techniques.
References
[1] S. Baruah, J. Dutta, Sci. Technol. Adv. Mater. 10 (2009) 1.
[2] G. Applerot, A. Lipovsky, R. Dror, N. Perkas, Y. Nitzan, R. Lubart, A. Gedanken, Adv.
Funct. Mater. 19 (2009) 842.
[3] Y. Wang, E. Laborda, C. Salter, A. Crossley, R.G. Compton, Analyst 137 (2012) 4693.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
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P36
Progress on studying the effect of alloying Pd with phosphorus
on the ethanol electrooxidation
S. Salomé, R. Rego, M. C. Oliveira
Departamento de Química/CQ-VR,
Universidade de Trás-os-Montes e Alto Douro (UTAD), Portugal
Ethanol alcohol fuel cells have received much attention for portable applications due to their
advantages over analogous devices feed with hydrogen. Much effort has been devoted to
employ Pd-alloys on the ethanol electrooxidation reaction (EOR), looking for a synergetic
effect between Pd and the alloying element. However, the alloying element has been restricted
to another metal element, giving rise to bimetallic and even trimetallic alloys [1].
In this work, the electrocatalytic behavior of Pd alloyed to a non-metal element (phosphorus)
towards EOR in the alkaline medium is investigated. The PdP alloy is prepared by electroless
deposition onto a carbon paper substrate previously activated by the electrodeposition of Pd
nucleus [2]. The effect of this procedure on the PdP alloy morphology and electrocatalytic
activity is analyzed using increasing Pd loadings. Comparison of the electrocatalytic activity
of PdP alloy and Pd electroless is evaluated from cyclic voltammetry, chronoamperometry
and electrochemical impedance spectroscopy, Figure 1. The long-term stability of the
electrodes is ascertained from 250 successive cycles recorded in 0.5 M EtOH + 0.5 M NaOH
and SEM/EDS analysis of the surface electrodes.
-0.6 -0.3 0.0 0.3 0.6
0.0
0.4
0.8
1.2
1.6
j/ m
A.c
m-2
E vs (Ag/AgCl)/ V
Pd
PdP c
a)
b)
Figure 1 – a) Cyclic voltammetry and b) Nyquist plot of ethanol oxidation on Pd electroless
and Pd-P alloy at -0.30 V in 0.5 M EtOH + 0.5 M NaOH solution.
[1] M.C. Oliveira, R. Rego, L.S. Fernandes, P.B. Tavares, Journal of Power Sources, 2011,
196, 6092–6098; [2] S. Salomé, R. Rego, A. Querejeta, F. Alcaide, M. Cristina Oliveira,
Electrochimica Acta (in press). DOI: 10.1016/j.electacta.2013.04.159
Keywords: DEFCs, Methanol, Ethanol, PdP alloy
Acknowledgments: FCT and COMPETE projects PTDC/QUI-QUI/110855/2009 and UI 686 -
2011-2012,PEst-C/QUI/UI0686/2011.
0 200 400 600 800 1000
0
200
400
600
800
1000
-Z "
/
Oh
m
Z ´ / Ohm
PdP
Pd
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
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P37
An electrochemical impedance spectroscopy study of oxygen reduction
kinetics on PdP alloys
Rosa Regoa, Sónia Salomé
a, Maria Cristina Oliveira
a, J. C. S. Fernandes
b
aDepartamento de Química/CQ-VR, Universidade de Trás-os-Montes e Alto Douro, 5001-801
Vila Real bICEMS / DEQ, Instituto Superior Técnico, Technical University of Lisbon, Av. Rovisco Pais
1049-001 Lisboa, Portugal [email protected]
To make proton exchange membrane fuel cells (PEMFCs) competitive to applications in the
transportation, stationary, and portable/micro power generation, new effective low cost
electrocatalysts must be developed. Palladium alloys (Pd-Co, Ni, Cr and Cu) have been
introduced as cathode electrocatalysts for the oxygen reduction reaction (ORR) in acid medium
[1, 2]. It has also been shown that Pd and PdP exhibit interesting activity for the ORR reaction in
acid medium [3].
In the present study, electrochemical impedance spectroscopy (EIS) has been used to evaluate the
electrochemical performance of porous PdP-gas diffusion electrodes (GDE) for ORR in PEMFCs.
PdP-GDEs have been prepared by electroless deposition as described previously [3]. The aim of
this study is to understand the effect of catalyst coverage of the carbon paper support on the
electrochemical activity and resistance of PdP-GDE electrodes.
The catalysts have been studied in sulfuric and perchloric media and in the presence or absence of
methanol and/or nafion and their behavior have been compared with that exhibited by a platinum
electrocatalyst. The results indicate that, although the carbon paper support PdP coverage does not
influence the ohmic resistance, the charge transfer resistance is significantly affected. In addition,
the Nyquist plot (Figure 1) presents a single time constant that may be associated with a one-step
electron transfer reaction, from O2 to H2O formation.
0 500 1000 1500 2000 2500
0
500
1000
1500
2000
2500
0 500
0
500
Z'' /
ohm
Z' /ohm
0.1 M H2SO
4
0.1 M H2SO
4 + 0.5 M MeOH
0.1 M H2SO
4 + Nafion
0.1 M HClO4
Z''
/ohm
Z' /ohm
Figure 1. Nyquist plot of the ORR on PdP (load of 0.50 mg cm-2
) in O2-saturated solutions at 0.55 V.
[1] K. Oishi, O. Savadogo, Electrochimica Acta 98 (2013) 225; [2] D. C. Martínez-Casillas, G.
Vásquez-Huerta, J. F. Pérez-Robles, O. Solorza-Feria, Journal of Power Sources 196 (2011) 4468; [3]
R. Rego, A. M. Ferraria, A. M. Botelho do Rego, M. C. Oliveira, Electrochimica Acta 87 (2013) 73
Keywords: PdP-GDE, ORR, EIS
Acknowledgments: FCT and COMPETE projects PTDC/QUI-QUI/110855/2009 and UI 686 - 2011-2012,PEst-C/QUI/UI0686/2011.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
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P38
Building Biomimetic Lipid Raft Environments on Modified Gold for the
Study of Bioactive Molecule-Membrane Interactions
Joaquim T. Marquês, Rodrigo F. M. de Almeida, Ana S. Viana,
Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa
Campo Grande, Ed. C8
In search for improved biomimetic platforms, supported lipid bilayers (SLB) prepared on gold
currently occupy an important position whether in the development of lipid-based biosensor
interfaces or in the study of biomembrane-related cellular processes. Of special relevance is
lipid composition, in particular those combinations of lipids that lead to the formation of lipid
rafts, which are rarely employed on most of the reported studies of SLB on gold. In a previous
work we have shown, using a ternary lipid mixture (DOPC/DPPC/Cholesterol 2:2:1), that the
formation of a raft-containing lipid bilayer directly on gold is only possible in very strict
bilayer assembling conditions due to the hydrophobic nature of gold [1]. However, such
conditions may not be suitable for many experiments. Furthermore, modification of the metal
surface may be required to preserve the bioactivity of a membrane-inserted protein. We used
the same lipid mixture to find the suitable conditions for SLB formation and its properties on
modified gold surfaces with hydrophilic self-assembled monolayers (SAM) of 11-
mercaptoundecanoic acid (MUA) or cysteine (Cys). The interaction of ternary lipid vesicles
with the two SAMs was similar, as evaluated by surface plasmon resonance and quartz crystal
microbalance. For both SAMs the presence of a planar lipid bilayer was confirmed by atomic
force microscopy in buffer solution, Domains with nanometer differences, typical of lipid
rafts, were clearly observed. The thickness of the lipid films estimated by ellipsometry is that
expected for a lipid bilayer.
Due to their tight packing MUA SAMs block the access of electroactive molecules to the
substrate, whereas shorter monolayers such as Cys might be suitable for the development of
lipid-based biosensor interfaces with electrochemical transduction. Therefore we used Cys-
modified electrodes to form raft-containing SLBs and study the interactions with a redox
active molecule, epinephrine. Cycilc voltammetry in buffer solution revealed that epinephrine
interacts differently with the SLB depending on lipid composition. Interestingly, fluorescence
spectroscopy revealed a rather weak interaction of epinephrine with lipid bilayers in
suspension, underlining the suitability of the platform cys-SLB to study and detect
membrane-associated processes with high sensitivity.
This work was financed by FCT: Ph.D. fellowship: SFRH/BD/64442/2009, grant PEst-
OE/QUI/UI0612/2013, and IF2012 initiative (POPH, Fundo Social Europeu).
[1] J. T. Marquês, R. F. M. de Almeida, A. S. Viana Soft Matter, 8 (2012) 2007-2016.
Keywords: Planar lipid bilayers; lipid rafts; chemically modified gold; atomic force
microscopy.
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
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3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
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AUTHOR LIST
Aaronson, B. D. B. PL1
Abrantes, L. M. OC2, P17
Almeida, I. P15
Almeida, M. G. OC3
Almeida, R. F. M. P38
Alves, G. M. S. P19
Araújo, M. P20
Barroso, M. F. P20, P26
Barsan, M. M. KN4
Bastos, A. C. P18
Bento, F. P4, P5, P6, P7
Bettencourt, A. P. P24
Brandão, L. OC1, P1
Brett, C. M. A. KN4
Brito, A. G. KN5
Cabrita, J. F. P17, P29
Calhorda, M. J. P12
Carmezim, M. J. P2
Carneiro, P. P25
Carvalho, M. A. P24
Carvalho, M. D. P16
Carvalho, R. P10
Cass, A. E. G. P33
Castela, A. S. P23, P27
Cavaleiro, J. A. S. P22
Celorrio, V. PL2
Chen, C. PL1
Coelho, S. C. P25
Colburn, A. W. PL1
Correia, C. P24
Correia, A. N. P20
Correia, J. P. P22
Costa García, A. PL3
Costa, M. F. M. P21
Costa, S. P26
Cruz, D. P26
Cuharuc, A. PL1
Delerue-Matos, C. KN2, P20, P25, P26
Dias, L. P28
Dionísio, N. P11
Domingos, R. F. P9
Duarte, A. J. P26
Duarte, R. G. P27
Dutra, R. A. F. P33
Eblagon, K. OC1
Eug nio S P2
Faria, C. A. P8
Fermín, D. J. PL2
Fernandes, J. C. S. P37
Fernandes, P. M. V. P35
Ferreira, M. KN5
Ferreira, M. G. S. KN3, P18
Ferreira, N. S. P30, P32
Ferreira, V.C. OC2
Figueira, R. B. P34
Figueiredo, J. L. KN5
Florez, J. PL2
Fonseca, A. M. KN5
Fortes, M. P5
Fortunato, E. OC4
Franco, C. P9
Freire, C. P20
Geraldo, D. P4, P5, P6, P7
Gomes, M. J. M. P21
Gonçalves, L. M. P8
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
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Gonzalez-Costas, J. P7
Gonzalez-Romero, E. P7
Güell, A. G. PL1
Gusmão, R. P5, P13
Henriques, F. P16
Lai, S. C. S. PL1
Lazenby, R. A. PL1
Leite, A. C. P24
Lima-Neto, P. P20
Lobo, F. P24
Loureiro, J. A. P25
Macpherson, J. V. PL1
Magalhães, J. M. C. S. P19
Maia, F. P18
Marquês, J. T P38
Martinho, P. N. P12
Martins, L. L. P3
Martins, R. OC4
Matos, A. I. P3
McKelvey, K. PL1
Meadows, K. E. PL1
Meirinho, S. G. P28
Melato, A. I. OC2, P12
Monteiro, O. C. P29
Montemor, M. F. P2, P23
Montforts, F. P. P17
Morais, S. P20, P25
Moreira, A. P. T. P31
Moreira, F. T. C. P31, P33
Moreira, S. D. F. C. P21
Moura, J. J. G. OC3
Mourato, M. P. P3
Nadappuram, B. P. PL1
Neto, M. M. M. P3
Neves, C. M. B. P22
Neves, I. C. KN5
Neves, M. G. P. M. S. P22
Neves, R. P23
Nogueira, R. KN5
Noronha, J. P. C. P33
Nunes Correia, A. P20
Oliveira, M. B. P. P. P20
Oliveira, M. C. P11, P36, P37
Oliveira, R. P4, P5, P6, P7
Oliveira, T. M. B. F. P20
Órfão, J.J.M. KN5
Ornelas, I. M. P22
Paiva, C. P5
Parpot, P. KN5
Pastor, E. PL2
Patel, A. N. P15
Pedroso, H. A. OC3
Peixoto, L. KN5
Pereira, C. M. P13, P35
Pereira, E. V. P34
Pereira, L. OC4, P14
Pereira, M. C. P25
Pereira, M. F. R. KN5, OC3
Peres, A. M. P28
Pimpão, M. OC3
Pinheiro, J. P. P9, P10
Pinto, M. F. KN5
Plana, D. PL2
Prathish, K. P. KN4
Proença, M. F. P5, P24
Ramalhosa, M. J. P26
3ª Jornadas de Electroquímica e Inovação 2013 www.e-inov.org
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Realista, S. P12
Rego, R. P36, P37
Ribeiro, J. A. P35
Rocha, M. M. P3
Rodrigues, L. R. P28
Rodrigues, P. R. S. OC3
Sales, M. G. F. P30, P31, P32, P33
Salomé, S. P36, P37
Salta, M. M. P34
Santos, A. C. G. P14
Santos, L. OC4
Sharma, S. P33
Silva, C. J. R. P21, P34
Silva, F. P35
Silva, J. P. B P21
Silva, R. P. P2
Silva, T. M. P2
Silveira, C. M. OC3
Soares, H. M. V. M. P19
Soares, O. S. G. P. KN5
Sousa, R. P8
Tedim, J. KN3, P18
Truta, L. A. A. N. A. P32
Unwin, P. R. PL1
Velders, A. P10
Viana, A. S. KN1, P15, P16, P17,
P22, P38
Vicente, C. P23, P27
Vilas Boas, A. P6
Vrouweb, E. P10
Wojcik, P. OC4
Zhang, G. PL1
Zheludkevich, M. L. KN3, P18
LIST OF PARTICIPANTS
Almeida Inês Faculdade de Ciências da Universidade de Lisboa
Lisboa [email protected]
Baião Vanessa Faculdade de Ciências da Universidade de Lisboa
Lisboa [email protected]
Bastos Alexandre Universidade de Aveiro
Aveiro [email protected]
Barsan Madalina Faculdade de Ciências e Tecnologia Universidade de Coimbra
Coimbra [email protected]
Bento Fátima Universidade do Minho
Braga [email protected]
Bermudez Verónica Universidade de Trás-os-Montes e Alto Douro
Vila Real [email protected]
Bettencourt Ana Universidade do Minho
Braga [email protected]
Brandão Lúcia FEUP
Universidade do Porto
Porto [email protected]
Cabrita Joana Faculdade de Ciências da Universidade de Lisboa
Lisboa [email protected]
Carneiro Pedro FEUP
Universidade do Porto
Porto [email protected]
Carvalho Rui Micronit Microfluidics
Enschede (Holanda)
Correia Jorge Faculdade de Ciências da Universidade de Lisboa
Lisboa [email protected]
Costa Sofia REQUINTE Instituto Superior de Engenharia do Porto
Porto [email protected]
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Cruz Diana REQUINTE
Instituto Superior de Engenharia do Porto
Porto [email protected]
Faria Carlos Universidade do Minho MicroNanotechnol. and Biomedical Applications
Guimarães [email protected]
Fermin David University of Bristol Bristol [email protected]
Fernandes João Salvador
Instituto Superior Técnico
Lisboa [email protected]
Fernandes Mariana Universidade de Trás-os-Montes e Alto Douro
Vila Real [email protected]
Ferreira Nádia Instituto Superior de Engenharia do Porto
Porto [email protected]
Ferreira Virgínia Faculdade de Ciências da Universidade de Lisboa
Lisboa [email protected]
García Agustín University of Oviedo
Oviedo [email protected]
Geraldo Maria Dulce
Universidade do Minho
Braga [email protected]
Gonçalves Luís Universidade do Minho MicroNanotechnol. and Biomedical Applications
Guimarães [email protected]
Gusmão Rui Universidade do Minho
Braga [email protected]
Henriques Filipa Isabel
Faculdade de Ciências da Universidade de Lisboa
Lisboa [email protected]
Maia Frederico Universidade de Aveiro
Aveiro [email protected]
Marquês Joaquim Faculdade de Ciências da Universidade de Lisboa
Lisboa [email protected]
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Matos Ana Faculdade de Ciências da Universidade de Lisboa
Lisboa [email protected]
Matos Cristina Delerue
REQUINTE
Instituto Superior de Engenharia do Porto
Meirinho Sofia Universidade do Minho
Departamento de Eng. Biologica
Lisboa [email protected]
Melato Ana Faculdade de Ciências da Universidade de Lisboa
Lisboa [email protected]
Monteiro Olinda Faculdade de Ciências da Universidade de Lisboa
Lisboa [email protected]
Moreira Ana Instituto Superior de Engenharia do Porto
Porto [email protected]
Oliveira Maria Cristina
Universidade de Trás-os-Montes e Alto Douro
Vila Real [email protected]
Oliveira Raquel Universidade do Minho
Braga [email protected]
Ornelas Isabel Faculdade de Ciências da Universidade de Lisboa
Lisboa [email protected]
Pereira Carlos Faculdade de Ciências da Universidade do Porto
Porto [email protected]
Pinheiro Jose Paulo Universidade do Algarve
Faro [email protected]
Proença Luis ISCS Egas Moniz Almada [email protected]
Realista Sara Faculdade de Ciências da Universidade de Lisboa
Lisboa [email protected]
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Rego Rosa Universidade de Trás-os-Montes e Alto Douro
Vila Real [email protected]
Ribeiro José Faculdade de Ciências da Universidade do Porto
Porto [email protected]
Santos Ana Catarina
CENIMAT - I3N FCT - Universidade Nova de Lisboa
Lisboa anacatarinasantos123@gmail.
com
Santos Lídia CENIMAT - I3N FCT - Universidade Nova de Lisboa
Lisboa [email protected]
Salomé Sónia Universidade de Trás-os-Montes e Alto Douro
Vila Real [email protected]
Silva Carlos Universidade do Minho
Braga [email protected]
Silva Rui Pedro Instituto Superior Técnico
Lisboa [email protected]
Silveira Célia REQUIMTE - FCT Universidade Nova de Lisboa
Lisboa [email protected]
Soares Helena ICETA / REQUIMTE/FEUPUniversidade do Porto
Porto [email protected]
Truta Liliana Instituto Superior de Engenharia do Porto
PORTO [email protected]
Unwin
Patrick University of Warwick
Warwick [email protected]
Vaz Pereira Elsa LNEC Lisboa [email protected]
Viana Ana Faculdade de Ciências da Universidade de Lisboa
Lisboa [email protected]
Vicente Cilene Instituto Politécnico de Setúbal
Setúbal [email protected]
Zheludkevich
Mikhail
CICECO Universidade de Aveiro
Aveiro [email protected]
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