Preparation of Monodisperse Enrofloxacin Molecularly...

Research ArticlePreparation of Monodisperse Enrofloxacin MolecularlyImprinted Polymer Microspheres and Their RecognitionCharacteristics

XiaoxiaoWang1 Yanqiang Zhou1 Yuling Niu2 Shanwen Zhao1 and Bolin Gong 1

1College of Chemistry and Chemical Engineering North Minzu University Yinchuan 750021 China2Ningxia Entry-Exit Inspection and Quarantine Bureau Comprehensive Technology Center Yinchuan Ningxia China

Correspondence should be addressed to Bolin Gong gongbolin163com

Received 27 December 2018 Revised 2 February 2019 Accepted 5 March 2019 Published 1 April 2019

Academic Editor Bogusław Buszewski

Copyright copy 2019 XiaoxiaoWang et alThis is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

This study presents a new strategy for the detection of enrofloxacin (ENR) in food samples by the use of monodisperse ENRmolecularly imprinted polymers (MIPs) Using enrofloxacin as template molecule methacrylic acid as functional monomer andethylene diglycidyl ether as cross-linker surfacemolecularly imprinted polymers (MIPs) were prepared on the surface of polymericglycidyl methacrylate-ethyleneglycol dimethacrylate (PGMA-EDMA) microspheresThe surfacemorphology and imprinting behaviorof PGMA-EDMAMIPs were investigated and optimized Synthesized PGMA-EDMAMIPs showed good physical and chemical stabilityand specific recognition toward fluoroquinolones The introduction of PGMA-EDMA microspheres greatly increased the adsorptionarea of PGMA-EDMAMIPs and increased the adsorption capacity of target molecules The core shell structure increased theadsorption rate and adsorption equilibrium was achieved within 6 min much higher than that of MIPs synthesized by traditionalmethods Enrofloxacin in milk samples was detected by molecular imprinting solid phase extraction (MISPE) combined with highperformance liquid chromatography (HPLC) Implementing this method resulted in a recovery rate of 946sim1096 with a relativestandard deviation (RSD) of less than 32 The limit of detection (LOD) of this method was identified as three times the signal-to-noise ratio (10 120583gL) In summary this work proposed a sensitive rapid and convenient method for the determination of traceENR in food samples

1 Introduction

Enrofloxacin (ENR) is an antibiotic belonging to the fluoro-quinolone class (FQs) of synthetic antibiotics The physico-chemical properties and broad spectrum of activity of FQsantibiotics against most bacteria have led to their widespreaduse in human medicine as well as the prevention andtreatment of animal diseases in livestock [1ndash3] Howevertrace amounts of these drugs can be detected in food productstaken from animals treated with FQs antibiotics posing athreat to human health (such as toxicity drug resistance andanaphylaxis) [4] In fact many countries have establisheda maximum limit of FQs residues in food Additionallythe environmental impact of FQs residues has recentlyattracted worldwide attention Therefore sensitive and selec-tive method for the detection and quantification of FQs is animportant area of research The currently available methods

for the detection of FQs in different environments consist ofhigh performance liquid chromatography [5] coupled tomassspectrometry [6 7] ultraviolet (UV) [8] and fluorescencedetection[9 10] However the complex matrices of biologicalsamples present challenges for the selective quantification oftrace amounts of FQs in food products

Molecularly imprinted technology (MIT) [11ndash13] is amethod that can be used to develop polymers for the selectiveidentification of a particular molecular target or a classof molecules [14] To prepare the polymer a functionalmonomer is constructed with binding sites matching theshape size and functional groups of a template moleculeThe functional monomers are then copolymerized and cross-linked in the presence of the template molecule to create apolymer network capable of molecular recognition Subse-quent removal of the template molecules from the polymernetwork facilitates the selective binding and recognition of

HindawiInternational Journal of Analytical ChemistryVolume 2019 Article ID 5970754 10 pageshttpsdoiorg10115520195970754

2 International Journal of Analytical Chemistry

the template molecule or structural analogs in a samplemixture [15] MIPs are attractive materials for molecularrecognition due to their low cost simple preparation highstability and good reproducibility under harsh chemical andphysical conditions Consequently MIT has been widelyused in extraction separation [16 17] chemical sensing[18] catalysis [19] and chiral separations [20ndash22] Surfacemolecular imprinting distributes almost all binding sites ona surface with good accessibility by taking some measureswhich facilitates the removal and recombination of templatemolecules This method is therefore particularly suitablefor the preparation of imprinted polymers of biomacro-molecules The distribution of binding sites across the poly-mer surface shortens the adsorption equilibrium time byovercoming the traditional embedding phenomenon [23 24]

The preparation of MIPs using ENR as a templatemolecule has been recently explored in the literature theresulting MIPs would have important implications for theselective detection of ENR in complex matrices Xiao et al[25] prepared FQs imprinted polymers on the surface ofmag-netic carbon nanotubes and simultaneously used a pseudotemplate to achieve fluoroquinolone extraction Additionallywork by He et al [26] firstly attempted to prepare an ENRimprinted material using the magnetic polyhedral oligomericsemi-siloxane composite as a matrix In a similar vein Yan etal [27] thermally initiated polymerization of the monolithiccolumn and use norfloxacin as a pseudo template for ENRthe resulting material demonstrated a high affinity for ENRand norfloxacin in water and successfully afforded the extrac-tion of ENR and norfloxacin from blood samples Despitethese great advancements in the development of MIPs thepreparation of monodisperse ENR imprinted polymers bysurface grafting and the application of the resultant polymersto a real sample analysis have yet to be reported

In this work self-made monodisperse macroporouscross-linked polymeric glycidyl methacrylate-ethylene glycoldimethacrylate (PGMA-EDMA) microspheres are used as thematrix Compared with silica gel and other carriers it is moreresistant to acid and alkaliand has a large number of activegroups on the surface It is an ideal molecularly imprintedcarrier A surface grafting technique was used to prepareenrofloxacin molecular imprinted polymers attached to thesurface of PGMA-EDMA microspheres via MPS modified sitesThe surface structure and the physicochemical properties ofthe polymers were analyzed and used for the detection of fourFQs in milk samples

2 Materials and Method

21 Reagent and Instrument Enrofloxacin (ENR) tetracy-cline (TC) ofloxacin (OFL) chloramphenicol (CAP) gly-cidyl methacrylate (GMA) ethylene glycol dimethacrylate(EDMA) ethylene glycol diglycidyl ether (EGDE) meth-acrylic acid (MAA) ammonium persulfate [(NH4)2S2O8]3-methacryloylpropyl trimethoxysilane (MPS) styrene (St)azobisisobutyronitrile (AIBN) polyvinylpyrrolidone (PVP)cyclohexanol poly(vinyl alcohol) (PVA) dibutyl phthalate(DBP) ethyl alcohol pyridinemethanol acetone acetic acidsodium dodecyl sulfate(SDS)and tetrahydrofuran (THF)

were purchased from Aladdin Reagent (Shanghai China)HPLC grade methanol and acetonitrile were obtained fromSigma (St Louis MO USA) Milk samples were purchasedfrom a local supermarket The polymerization inhibitor wasremoved from the MAA by using a vacuum distillation unitWater was twice distilled prior to use All other reagentswere of analytical grade and usedwithout further purificationunless otherwise specified All solutions prepared for HPLCwere filtered through a 045120583m nylon filter before use

Chromatographywas performed using anLC-20AT chro-matographic system (Shimadzu Japan) equipped with twoLC-20AT pumps and a SPD-20A UVndashVIS detector Sampleswere injected through a Rheodyne 7725 valve Polymersmorphology was characterized by using a JSM-7500F elec-tron scanning microscope (JEOL Co Japan) Elementalanalysis was performed on a VarioEL III elemental analyzer(Elementar Co Germany) Infrared spectra were collectedby using a Fourier transform infrared spectrometer (Shi-madzu Japan) Absorption spectra were collected by using aTU-1810-type ultraviolet spectrophotometer (BeijingGeneralInstrument Co Ltd China) Centrifugation was performedwith a TG16-WS high-speed centrifuge (Centrifuge FactoryChina)

22 Preparation of Monodisperse 119875119866119872119860-119864119863119872119860 MicrospheresMonodisperse polystyrene seeds (PS) were synthesizedaccording to a dispersion polymerization method Themonomer styrene (10 mL) initiator ABIN (02 g) stabilizerPVP (2 g) and anhydrous ethanol (878 mL) were combinedin a 100 mL single-necked flask and sonicated until all of thestyrene ABIN and PVP were dissolved The flask was thenattached to a rotary device equippedwith a heating apparatusPolymerization was carried out at 70∘C over the course of 24h Upon completion of the reaction the solvent was removedby centrifugation and the remaining solids were washed withcopious amounts of ethanol to obtain the desired PS

In a 150 mL single-necked flask GMA (6 mL) ABIN(036 g) EDMA (6 mL) DBP (6 mL) and cyclohexanol (6mL) were combined and sonicated to dissolve completelythen 45 mL distilled water 75 mL 02 SDS solution and35 mL 5 PVA solution were added to the above mixedsolution The reaction mixture was subjected to ultrasonicemulsification for 30 min until complete emulsification ofthe organic phase was achieved The resultant emulsion wasslowly added to a solution of the prepared monodisperse PSwhile the temperature was maintained at 30∘C The reactionmixtureswere stirred for 24 h thendegassed under a nitrogenatmosphere for 20 min and still stirred at 70∘C for additional24 h The solids obtained were washed with water methanoland acetone and then dried in vacuo to yield the productTheporogens were removed by extraction with tetrahydrofuranfor 48 h in a Soxhlet apparatus for products The productswere washed with methanol again and dried in vacuo to yieldthe PGMA-EDMA microspheres

PGMA-EDM (20 g) were suspended in 100 mL of 01 molLsulfuric acid stirred and kept at 60∘C for 12 h Then theproducts were filtered and washed with water until neutraland then dried under vacuum to afford the hydrolyzedPGMA-EDMA microspheres

International Journal of Analytical Chemistry 3

23 Preparation of 119875119866119872119860-119864119863119872119860MIPs

231 Bonding of MPS on the Surface of 119875119866119872119860-119864119863119872119860 Thehydrolyzed microspheres PGMA-EDMA (20 g) were ultrason-ically dispersed in 100 mL of 50 (VV) ethanol MPS (25mL) and pyridine (3 drops) were added to the dispersionand the mixtures were heated to 50∘C for 24 h Unreactedsilylation reagent was removed from the mixture by vac-uum filtration using absolute ethanol The products wereconcentrated in vacuo to obtain the modified microspheresPGMA-EDMAMPS

232 GraingMAA on119875119866119872119860-119864119863119872119860MPS ThePGMA-EDMAMPS (20 g) microspheres and MAA (7 mL) were combinedin 150 mL of water and (NH4)2S2O8 (0042 g) were addedas an initiator for the graft polymerization reaction Thereactant mixtures were heated to 70∘C for 24 h whileconstantly stirring under an atmosphere of nitrogen Theresultant microspheres were purified by Soxhlet extraction inethanol to remove unreacted MAA physically attached to themicrospheres The solution was dried in vacuo to yield thegrafted PGMA-EDMAMPSMAAmicrospheres

233 Preparation of MIPs The PGMA-EDMAMPSMAA(20 g) microspheres were dissolved in 50mL 10mmolL ENRmethanol solution The mixtures were shaken at 25∘C for 6h until the adsorption of ENR by PGMA-EDMAMPSMAAreached equilibrium The reactant mixtures were then fil-tered and the ENR-adsorbed microspheres PGMA-EDMAMPSMAA were dried under vacuum The ENR-adsorbedPGMA-EDMAMPSMAAmicrospheres (20 g)were added to50mL 4 mmolL ENR 50 aqueous methanol solution ThepH of the solution was adjusted to 80 using NaOH solutionand then EGDE (25 mL) was added as a cross-linker Thereactant mixture was stirred at 50∘C for 8 h to completepolymerization After the reaction finished the productwas washed with methanol and dried at 60∘C The MIPmaterial was extracted with Soxhlet using methanolaceticacid (91 vv) mixture to remove the unreacted cross-linkerEGDE and residual template The non-imprinted polymers(PGMA-EDMANIPs) were synthesized according to the sameprocedures described above except in the absence of atemplate molecule

24 Adsorption Experiments To measure the adsorptioncapacity of the polymers the PGMA-EDMAMIPs (20 mg)was mixed with a series of methanol solutions of ENR atvarious concentrations Each reactant mixture was shakenfor 12 h and then subjected to centrifugation Supernatantwas quantified by UV spectrometry at 280 nm and then theadsorption amount was calculated according to

119876 =(1198620 minus 119862119890) 119881

119898(1)

where Q (mgg) represents the mass of ENR adsorbed pergram of polymer119862o (mgL) and 119862e (mgL) are the initial andfinal concentrations of ENR in solution respectively V (L)is the total volume of the solution and m (g) is the mass ofpolymer

For the kinetic experiments the PGMA-EDMAMIPs (20mg) was added to a methanol solution of ENR (10 mL2 mM) The series of prepared reaction mixtures weremechanically shaken for different lengths of adsorption timeat room temperature after which each of the mixtures wassubjected to centrifugation to afford separation Supernatantwas quantified by UV spectrometry at 280 nm and then theadsorption amount was calculated according to (1)

The operation procedures of PGMA-EDMANIPs were thesame as those of PGMA-EDMAMIPs

25 Selective Adsorption Experiments To investigate theselectivity of the prepared PGMA-EDMAMIPs towards ENRthe binding of ENR was tested in comparison to threestructural analogs ofloxacin (OFL) tetracycline (TC) andchloramphenicol (CAP) (Figure 1) The PGMA-EDMAMIPs(20 mg) was added to flasks containing methanol solutions(10 mL 2 mM) of ENR The shaking adsorption processwas carried out for 12 h at 25∘C The adsorption capacity ofPGMA-EDMAMIPs to OFL TC and CAP was determined inthe same wayThe operation procedures of PGMA-EDMANIPswere the same as those of PGMA-EDMAMIPs

The distribution coefficients (KD) selectivity coefficients(k) relative selectivity coefficients (1198961015840) and imprinting factor(120572) of OTC and CTC with respect to TC can be obtainedaccording to the following equations

119870119863 =119876119890119862119890

(2)

119896 =119870119863(119865119876119904)119870119863(119879119862)

(3)

1198961015840 =119870119872119868119875119904119870119873119868119875119904

(4)

120572 =119876119872119868119875119904119876119873119868119875119904

(5)

where Qe (mgg) and Ce (mgL) represent the amountof binding and concentration of substrate at equilibriumrespectively KD(FQS) represents the distribution coefficientsof the fluoroquinolones KD(TC) represents the distribu-tion coefficients of the tetracyclines and KMIPs and KNIPsare the selectivity coefficients of the PGMA-EDMAMIPsand PGMA-EDMANIPs respectively QMIPs and QNIPs repre-sent the adsorption capacity of the PGMA-EDMAMIPs andPGMA-EDMANIPs for ENR respectively

26 Spiked Recovery Experiments and Analysis of Actual Sam-ples A sample of milk (05 mL) solution was combined withacetonitrile (05 mL) solution homogenized This mixturesolution contained ENR and its concentration was 0025mmolL The samples were centrifuged for 5 min at a speedof 10000 rpmThe supernatant was collected and diluted withphosphate buffer solution (PBS PH 6 025 mM) to 10 mL

A SPE column filled with PGMA-EDMAMIPs orPGMA-EDMANIPs was activated with methanol (2 mL)and pure water (2 mL) successively The spiked milksample (3 mL) was flowed through the column and then


F

N

OH

O

N

O

N

(ENR)

OH O

OH

NH2

OOOH

HO HCH3 N(CH3)2

OH

(TC)

N N

FO

ON

OH

O

(OFL)

OH

N

OH

HN

Cl Cl

OO

O

(CAP)

minus+

Figure 1 The structures of ENR TC OFL and CAP

a methanolacetic acid (91 vv) solution (3 mL) wasused to elute the extracted analytes The collected eluatewas concentrated by N2 stream and then dissolved againwith 1 mL mobile phase Finally 20 120583L samples weredetected by HPLC (LC-20AT Shimadzu corporation)Chromatographic conditions stationary phase C18 reversedphase chromatographic column (150 mmtimes46 mm AgilentCorporation USA) Mobile phase 0025molL phosphoricacid solution (adjust PH to 30 with triethylamine)(A)simacetonitrile (B) Flow rate 08 mLmin The detectionwavelength is 278 nm by UV detector

3 Results and Discussion

31 Preparation of Enrofloxacin-Imprinted119875119866119872119860-119864119863119872119860MIPsTo introduce polymerizable double bonds to the surfaceof the PGMA-EDMA microspheres for facile preparation ofthe PGMA-EDMAMIPs the microsphere surface was modi-fied with coupling agent MPS Polymerization was initiatedto graft the functional monomer MAA to the surface ofmicrospheres and the resultant PGMA-EDMAMPSMAAmicrospheres were saturated to adsorb ENR By addingthe cross-linker EGDE to the microspheres under alka-line conditions a ring-opening reaction between the epoxygroup on the cross-linking agent and the carboxyl groupon the PGMA-EDMAMPSMAA macromolecule forms anetwork which encapsulated the ENRmolecule and therebygained ENR molecularly imprinted polymer The ENRwas then extracted from the PGMA-EDMAMIPs using amethanolacetic acid (91 vv) mixture creating holes inthe thin layer of the polymer well matched for the sizeand intermolecular interactions required for ENR bindingThe preparation of the PGMA-EDMAMIPs is summarized inFigure 2

32 Characterization of Enrofloxacin-Imprinted 119875119866119872119860-119864119863119872119860MIPs FT-IR analysis of PGMA-EDMAMIPs and the precur-sormaterials is shown in Figure 3Thehydrolyzed PGMA-EDMAmicrospheres exhibit a strong absorption peak at 1727 cmminus1corresponding to the stretching vibration of carbonyl grafted

to the microsphere characteristic -CH stretching vibrationsare noted at 2955 cmminus1 and an -OH stretching vibration isnoted at 2955 cmminus1 as a broad absorption peak The prepa-ration of PGMA-EDMAMPS depends on the reaction of thesilanylated reagent MPS with hydroxyl groups of the micro-sphere surface the observed decrease in the intensity of thecharacteristic -OH peak at 3525 cmminus1 in PGMA-EDMAMPSrelative to the precursor microspheres is attributed to thepartial consumption of the surface -OH functional groupsThe spectra of the PGMA-EDMAMIPs show an increase inintensity of a peak around 1093 cmminus1 corresponding to -C-O-C stretching vibrations in the EGDE cross-linker Moreoverthe absorption peak at 3525 cmminus1 is enhanced due to thereaction of the carboxyl groups of PGMA-EDMAMIPswith theepoxy groups on the cross-linker molecules which generatesadditional free hydroxyl groups

The SEManalysis of the PGMA-EDMAMIPs and precursorPGMA-EDMA microspheres are depicted in Figure 4 The leftimage in Figure 4 is an SEM image of the PGMA-EDMA micro-spheres the surface of PGMA-EDMA microsphere is dividedinto uniform pores formed during the one-step seed swellingand polymerization process used for microsphere prepara-tion A comparison of the SEM image of the PGMA-EDMAmicrospheres with that of the PGMA-EDMAMIPs prepared bysurface modification (Figure 4 right) reveals the presence ofregular gaps in the surface of the PGMA-EDMAMIPs createdupon removal of the template molecule The particle size ofPGMA-EDMAMIPs is about 5 120583m and its surface is porous

The PGMA-EDMA microspheres and PGMA-EDMAMPS andPGMA-EDMAMIPs microspheres were characterized by ele-mental analysis The results of these measurements arelisted in Table 1 The elemental analysis reveals an increasein carbon content of PGMA-EDMAMPS to the startingmaterial PGMA-EDMA indicating a successful grafting ofMPS to the surface of the microspheres The data for thePGMA-EDMAMIPs indicates an increase in both nitrogenand carbon composition This increase in NC content isconsistent with the successful grafting of the cross-linkingagent EGDE to the surface of the microspheres


F

NOH

O

N

O

N

EDMA GMA AIBNSDS PVA

C OCH2CHO

CH2

O 01 molL H2SO4 CO

OCH2CH CH2

OH OH

MPS

Si O CH2

CH3

O

H3COH3CO

H3CO

MAA EGDE AIBN

Enrofloxacin Rebinding enrofloxacin

Removal enrofloxacin

ENR

COH

OCOHO

CHO O

COH

OCOHO

CHO O

PGMA-EDMA

PGMA-EDMAMPS

PS

Figure 2 Schematic expression of the reaction process used to prepare PGMA-EDMAMIPs

4000 3500 3000 2500 2000 1500 1000 500

116429553525

1463

1727

Tran

smitt

ance

()

Wavenumber (cm-1)

a

b

c

Figure 3 FT-IR spectra of PGMAEDMA (a) PGMAEDMAMPS (b)and PGMA-EDMAMIPs (c)

Table 2 shows the specific surface area pore volumeand average pore size of PGMA-EDMA PGMA-EDMAMIPsand PGMA-EDMANIPs from nitrogen adsorption-desorptionanalysis As can be seen from (Table 2) the specific surfacearea of PGMA-EDMAMIPs decreases markedly with respect toPGMA-EDMA which is due to the fact that PGMA-EDMAMIPsis based on PGMA-EDMA to prepare imprinted polymerPGMA-EDMAMIPs have larger specific surface area porevolume and average pore size than PGMA-EDMANIPs Theresults showed that the different adsorption properties of

PGMA-EDMAMIPs and PGMA-EDMANIPs could not only becompletely attributed to the difference in morphology butalso be related to the imprinting process that producedspecific recognition sites Larger pore volume and averagepore size provide complementary spatial structures for selec-tive recognition of template molecules and competitors withPGMA-EDMAMIPs

33 Absorption Performance

331 Absorption Capacity and Kinetics The adsorptionisotherm data of the PGMA-EDMAMIPs were analyzed usingScatchard [28] model and processed according to the follow-ing equation

119876

119862119890= minus119876

119870119889+119876119898119886119909119870119889

(6)

where Q and Qmax are the experimental adsorption capacityto the template ENR(mgg) and the theoretical maximumadsorption capacity of the polymer (mgg) respectively Ce isthe concentration of ENR in equilibrium in solution (mgL)after adsorption and Kd is the dissociation constant (mgL)

The Scatchard model was implemented on the adsorptionisotherm data of the PGMA-EDMAMIPs and PGMA-EDMANIPs and the Scatchard figure created by plotting Q againstQCe (Figure 5) The Scatchard analysis curve of thePGMA-EDMAMIPs consists of two lines with different slopeswhile the Scatchard analysis curve of the PGMA-EDMANIPsis in a straight line suggesting the fact that while thePGMA-EDMANIPs only has a single binding site for ENRPGMA-EDMAMIPs exhibits two distinct binding sites One ofthe binding sites of the PGMA-EDMAMIPs is a nonspecific


Figure 4 Scanning electron micrographs of PGMA-EDMA microspheres and PGMA-EDMAMIPs

Table 1 Elemental analysis results of PGMA-EDMAMIPs

Samples Elemental composition ()C N H

PGMA-EDMA 5495 0329 6599PGMA-EDMAMPS 5548 0233 6442PGMA-EDMAMIPs 5587 0506 5599

Table 2 Comparison of PGMA-EDMA and PGMA-EDMAMIPs from nitrogen adsorption-desorption analysis

Sample Surface area (m2∙gminus1) Pore Volume (cm3∙gminus1) Average Pore Size (nm)PGMA-EDMA 15058 0930 1192PGMA-EDMAMIPs 10343 072 2492PGMA-EDMANIPs 8502 056 860

Table 3 The results of the Scatchard analysis of PGMA-EDMAMIPs

Binding site Linear equation 119870d (mgL) 119876max (mgg)Low affinity Q119862e =-00009511Q+00825(R=09842) 105143 8674High affinity Q119862e=-000429Q+01203 (R=09183) 23310 2805

adsorption site similar to that in PGMA-EDMANIPs formed byhydrophobic hydrogen bonds and physical adsorption whilethe other is the high affinity specific recognition site createdby the imprinted hole The additional binding site of thePGMA-EDMAMIPs is responsible for the higher adsorptioncapacity and better selectivity of this system relative to thePGMA-EDMANIPs

The values of Kd and Qmax are calculated from the slopeand intercept of the linear segments in the Scatchard plotsrespectively The parameters defining PGMA-EDMAMIPswere obtained from the slope and intercept of Scatchardcurve and the results are shown in (Table 3)TheKd andQmaxvalues were similarly calculated for the PGMA-EDMANIPs tobe 226160 mgL and 5500 mgg respectively

Plots of the adsorption kinetics of the PGMA-EDMAMIPsin 2 mM solution of ENR are shown in Figure 6 A rapidadsorption of ENR by the PGMA-EDMAMIPs up to 905of the adsorption equilibrium is noted within the first5 min after which a significant decrease in the adsorp-tion rate occurs The adsorption equilibrium reached at6 min Conversely adsorption by the PGMA-EDMANIPswas slow within the first 3 min where the driving forceof adsorption has non-covalent interactions between ENR

and PGMA-EDMANIPs The enhanced binding of ENR byPGMA-EDMAMIPs is dependent on the interaction betweenENR and the imprinted holes of the PGMA-EDMAMIPsgenerated on the surface of microspheres during preparationFrom the kinetic data it is noted that the specific adsorptionby PGMA-EDMAMIPs occurs largely in the initial stage ofadsorption

The adsorption isotherm of ENR in the range of 0125-225 mM was obtained by static equilibrium adsorption Theabsorption curves showed in Figure 7 show that the adsorp-tion of PGMA-EDMAMIPs gradually increased with increasesin ENR concentration while rapid saturation was observedin the adsorption by PGMA-EDMANIPs Adsorption by thePGMA-EDMAMIPs was significantly greater than that ofPGMA-EDMANIPs at a given concentration The low adsorp-tion capacity of the PGMA-EDMANIPs was attributed to theweak interactions that form between the PGMA-EDMANIPsand substrate substrate binding interactions were derivedfrom the nonspecific adsorption of the polar groups on thePGMA-EDMANIPs surface to ENR In addition to nonspe-cific adsorption interactions PGMA-EDMAMIPs also con-tained holes matching the spatial structure and comple-menting the functional groups of ENR The holes in the


0 5 10 15 20 25 30 35 40000

002

004

006

008

010Q

Ce (

Lg)

Q (mgg)

(a)

2 4 6 8 10 12 140017

0018

0019

0020

0021

0022

0023

0024

0025

QC

e(L

g)

Q (mgg)

(b)

Figure 5 Scatchard analysis plot of the binding of ENR to the PGMA-EDMAMIPs (a) and PGMA-EDMANIPs (b)

0 2 4 6 8 100

5

10

15

20

25

30

35

Q (m

gg)

t (min)

PGMA-EDMAMIPsPGMA-EDMANIPs

Figure 6 Dynamic adsorption curves of PGMA-EDMAMIPs andPGMA-EDMANIPs

PGMA-EDMAMIPs surface had a memory function for theENR molecule and the difference in the adsorption amountof the PGMA-EDMAMIPs and PGMA-EDMANIPs polymerswas largely attributed to the specific adsorption of these holes

332 Absorption Selectivity As it can be seen from thedata presented in Table 4 and Figure 8 the distributioncoefficient Kd selectivity coefficient k imprinting factor 120572and relative selectivity coefficient 1198961015840 of adsorbent can bedetermined via competitive binding experiments As pre-dicted the adsorption of ENR and its structural analoguesby the PGMA-EDMAMIPs was greater than that by thePGMA-EDMANIPs The selectivity coefficient (k) defines theselectivity of an absorber over the template molecule Thek values of the PGMA-EDMAMIPs were all greater than the

00 05 10 15 20 250

5

10

15

20

25

30

35Q

(mg

g)

C (mmolL)PGMA-EDMAMIPsPGMA-EDMANIPs

Figure 7 Adsorption isotherm of PGMA-EDMAMIPs andPGMA-EDMANIPs

corresponding values for the PGMA-EDMANIPs suggestinga higher affinity of the PGMA-EDMAMIPs for the templatersquosstructural analogues than for other types of antibiotic [29]Moreover the relative selectivity coefficient 1198961015840 values wereall greater than 1 indicating that after removal of thetemplate molecule holes and special imprinting sites wereformed on the polymer surface complementing the shapeand functional groups of the template molecule AmongENR and its structural analogues PGMA-EDMAMIPs has thelargest imprinting factor 120572 value for ENR which indicatesthat PGMA-EDMAMIPs has stronger affinity and excellentselectivity for ENR

34 Analysis of Real Samples Solid phase extraction isafforded via a four-step process activation loading leaching


Table 4 The selective coefficient of the PGMA-EDMAMIPs and PGMA-EDMANIPs

Analyte Q (mgg) 119870d (mLg) k 120572 1198961015840

MIPs NIPs MIPs NIPs MIPs NIPsENR 3358 602 4672 1812 356 350 558 102OFL 2370 556 3279 769 2 50 149 426 167TC 1167 460 1313 517 mdash mdash 253 mdashCAP 497 177 769 2 74 mdash mdash 280 mdash

CAP

TC

ENR0

10

20

30

40

PGMA-EDMAMIPs

PGMA-EDMANIPs

Q (m

gg)

OFL

Figure 8 Binding isotherms of ENR OFL TC and CAP on thePGMA-EDMAMIPs and PGMA-EDMANIPs

and eluting Using water (3 mL) as leachate effectivelyremoves the endogenous components of biological samplesas demonstrated in Figure 9 Following C18 extractionthe variance in the recovery of interfering substances wasattributed to the type of nonspecific interaction betweenthe different components in the sample matrix and the C18adsorbent such as the difference betweenhydrophobic versushydrophilic interactions In molecularly imprinted polymersolid-phase extraction (MISPE) the PGMA-EDMAMIPs hasbetter selectivity for the target substrate resulting in highrecovery and a purer extraction

A standard curve for ENR detection was establishedover the concentration range 1000sim9000 120583gL to yield anexpression of y=132741x+74035 and a correlation coefficientof R=09986 Milk samples were spiked with ENR standardsolutions with concentrations of 100 120583gL 200 120583gL and 500120583gL As demonstrated in Table 5 the rate of recovery ofthe ENR from these samples measured between 946 and1096 upon extraction with the PGMA-EDMAMIPs with arelative standard deviation (RSD) between 11 and 32 Theminimum limit of detection (LOD) was determined to be 10120583gL by tripling the signal-to-noise ratio (Table 6) summa-rizes the results of the existing reports on the detection ofENR in the milk samples by different types of ENR imprintedmaterials These results demonstrate a high recovery rate formethodology of this study

0 2 4 6 8 10

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

ENR

c

b

a

Time (min)

Figure 9 The chromatogram of milk samples (a) initial milksample (b) sample after PGMA-EDMAMIPs treatment and (c)sample after C18-SPE treatment

4 Conclusions

Anovel core-shell PGMA-EDMAMIPswas prepared for simul-taneous separation and enrichment of four FQs in milksamples As PGMA-EDMA is easy to modify stable physico-chemical and thermal stability easily controllable synthesisconditions low cost small nonspecific adsorption and soon the prepared PGMA-EDMAMIPs had the advantagesof stable properties high selectivity and recovery ratePGMA-EDMAMIPs have been successfully applied to theenrichment and separation of FQs inmilk samplesThisworkprovides a versatile approach for fabricating well-constructedcore-shell PGMA-EDMAMIPs particles for rapid enrichmentand highly selective separation of target molecules in realsamples

Data Availability

The data used to support the findings of this study areincluded within the paper

Ethical Approval

This paper does not contain any studies with human partici-pants or animals performed by any of the authors


Table 5 Recoveries and RSDs of SPE-HPLC method for the spiked milk samples

Added concentration120583g Lminus1 Recoveries () RSD ()MIP 100 946 29

200 956 32500 1096 11

C18 100 726 40200 756 32500 783 44

Table 6 Comparison of the ENR-MIPs applied for milk samplesrsquo TCs detection with existing reports

Preparing methods Testmethod Analyte Linearity

range120583gsdotLminus1Limit of

detection120583gsdotLminus1 Recoveries References

Surface imprinting HPLC-UV ENR PEF 25ndash500 07 9204-9831 [29]Surface imprinting HPLC-UV ENR OFL DAN 50ndash1000 176-1242 756ndash1089 [28]Bulkpolymerization HPLC-UV ENR CIP mdash 6

5 826ndash935 [30]

Sacrificial surfaceimprinting HPLC-UV OFL ENR NOR 30ndash250 mdash 909-1021 [31]

Conflicts of Interest

We declare that we have no financial and personal relation-ships with other people or organizations that can inappro-priately influence our work The authors have declared noconflicts of interest

Authorsrsquo Contributions

Xiaoxiao Wang and Yanqiang Zhou contributed equally tothis work

Acknowledgments

This work was financially supported by the NationalNatural Science Foundation of China (no 21565001 andno 31271868) Key Project of North Minzu University(2015KJ30)

References

[1] M Pan Y Gu M Zhang J Wang Y Yun and S WangldquoReproduciblemolecularly imprintedQCMsensor for accuratestable and sensitive detection of enrofloxacin residue in animal-derived foodsrdquo Food Analytical Methods vol 11 no 2 pp 495ndash503 2017

[2] W P da Silva L H de Oliveira A L D Santos V SFerreira andMAG Trindade ldquoSample preparation combinedwith electroanalysis to improve simultaneous determination ofantibiotics in animal derived food samplesrdquo Food Chemistryvol 250 pp 7ndash13 2018

[3] Y Tang M Li X Gao et al ldquoPreconcentration of the antibioticenrofloxacin using a hollow molecularly imprinted polymerand its quantitation by HPLCrdquoMicrochimica Acta vol 183 no2 pp 589ndash596 2016

[4] Y Tang M Li X Gao et al ldquoA NIR-responsive up-conversionnanoparticle probe of the NaYF4ErYb type and coated with a

molecularly imprinted polymer for fluorometric determinationof enrofloxacinrdquo Microchimica Acta vol 184 no 9 pp 3469ndash3475 2017

[5] M J Schneider A M Darwish and D W Freeman ldquoSimul-taneous multiresidue determination of tetracyclines and fluo-roquinolones in catfish muscle using high performance liquidchromatography with fluorescence detectionrdquo Analytica Chim-ica Acta vol 586 no 1-2 pp 269ndash274 2007

[6] F Yu S Yu L Yu et al ldquoDetermination of residual enrofloxacinin food samples by a sensitive method of chemiluminescenceenzyme immunoassayrdquo Food Chemistry vol 149 pp 71ndash752014

[7] Y Xiao H Chang A Jia and J Hu ldquoTrace analysis ofquinolone and fluoroquinolone antibiotics fromwastewaters byliquid chromatographyndashelectrospray tandem mass spectrome-tryrdquo Journal of Chromatography A vol 1214 no 1-2 pp 100ndash1082008

[8] M Lillenberg S Yurchenko K Kipper et al ldquoSimultaneousdetermination of fluoroquinolones sulfonamides and tetracy-clines in sewage sludge by pressurized liquid extraction andliquid chromatography electrospray ionization-mass spectrom-etryrdquo Journal of Chromatography A vol 1216 no 32 pp 5949ndash5954 2009

[9] A Poliwoda M Krzyzak and P P Wieczorek ldquoSupportedliquid membrane extraction with single hollow fiber for theanalysis of fluoroquinolones from environmental surface watersamplesrdquo Journal of Chromatography A vol 1217 no 22 pp3590ndash3597 2010

[10] Y-B Luo Q Ma and Y-Q Feng ldquoStir rod sorptive extractionwith monolithic polymer as coating and its application tothe analysis of fluoroquinolones in honey samplerdquo Journal ofChromatography A vol 1217 no 22 pp 3583ndash3589 2010

[11] B Sellergren ldquoImprinted polymers with memory for smallmolecules proteins or crystalsrdquo Angewandte Chemie Interna-tional Edition vol 39 no 6 pp 1031ndash1037 2000

[12] B Gao J Wang F An and Q Liu ldquoMolecular imprintedmaterial prepared by novel surface imprinting technique forselective adsorption of pirimicarbrdquo Polymer Journal vol 49 no5 pp 1230ndash1238 2008


[13] Y R Gong Y Wang J B Dong et al ldquoPreparation of isopro-carb surface molecular-imprinted materials and its recognitioncharacterrdquo Chinese Journal of Analytical Chemistry vol 42 no1 pp 28ndash35 2014

[14] H Yan F Qiao and H R Kyung ldquoMolecularly imprinted-matrix solid-phase dispersion for selective extraction of fivefluoroquinolones in eggs and tissuerdquo Analytical Chemistry vol79 no 21 pp 8242ndash8248 2007

[15] Y Niu C Liu J Yang et al ldquoPreparation of tetracycline surfacemolecularly imprinted material for the selective recognition oftetracycline in milkrdquo Food Analytical Methods vol 9 no 8 pp2342ndash2351 2016

[16] YHu J PanK ZhangH Lian andG Li ldquoNovel applications ofmolecularly-imprinted polymers in sample preparationrdquo TrAC- Trends in Analytical Chemistry vol 43 pp 37ndash52 2013

[17] A Martın-Esteban ldquoMolecularly-imprinted polymers as a ver-satile highly selective tool in sample preparationrdquo TrAC -Trends in Analytical Chemistry vol 45 pp 169-170 2013

[18] M Trojanowicz ldquoEnantioselective electrochemical sensors andbiosensors A mini-reviewrdquo Electrochemistry Communicationsvol 38 pp 47ndash52 2014

[19] J Zhang M Zhang K Tang F Verpoort and T Sun ldquoPol-ymer-based stimuli-responsive recyclable catalytic systems fororganic synthesisrdquo Small vol 10 no 1 pp 32ndash46 2014

[20] F Rong X Feng C Yuan D Fu and P Li ldquoChiral separation ofmandelic acid and its derivatives by thin-layer chromatographyusing molecularly imprinted stationary phasesrdquo Journal ofLiquid Chromatography amp Related Technologies vol 29 no 17pp 2593ndash2602 2006

[21] J Yin G Yang and Y Chen ldquoRapid and efficient chiralseparation of nateglinide and its l-enantiomer on monolithicmolecularly imprinted polymersrdquo Journal of ChromatographyAvol 1090 no 1-2 pp 68ndash75 2005

[22] R J Ansell ldquoMolecularly imprinted polymers for the enan-tioseparation of chiral drugsrdquoAdvancedDrug Delivery Reviewsvol 57 no 12 pp 1809ndash1835 2005

[23] Y Li X Li C Dong J Qi and X Han ldquoA graphene oxide-based molecularly imprinted polymer platform for detectingendocrine disrupting chemicalsrdquo Carbon vol 48 no 12 pp3427ndash3433 2010

[24] Y Li X Li C Dong Y Li P Jin and J Qi ldquoSelective recog-nition and removal of chlorophenols from aqueous solutionusing molecularly imprinted polymer prepared by reversibleaddition-fragmentation chain transfer polymerizationrdquo Biosen-sors and Bioelectronics vol 25 no 2 pp 306ndash312 2009

[25] D Xiao P Dramou N Xiong et al ldquoPreparation of molec-ularly imprinted polymers on the surface of magnetic carbonnanotubes with a pseudo template for rapid simultaneousextraction of four fluoroquinolones in egg samplesrdquo Analystvol 138 no 11 pp 3287ndash3296 2013

[26] H-B He C Dong B Li et al ldquoFabrication of enrofloxacinimprinted organic-inorganic hybrid mesoporous sorbent fromnanomagnetic polyhedral oligomeric silsesquioxanes for theselective extraction of fluoroquinolones in milk samplesrdquo Jour-nal of Chromatography A vol 1361 pp 23ndash33 2014

[27] H Yan F Qiao and K H Row ldquoMolecularly imprinted mono-lithic column for selective on-line extraction of enrofloxacinand ciprofloxacin from urinerdquo Chromatographia vol 70 no 7-8 pp 1087ndash1093 2009

[28] Y Hiratsuka N Funaya H Matsunaga and J HaginakaldquoPreparation of magnetic molecularly imprinted polymers for

bisphenol A and its analogues and their application to the assayof bisphenol A in river waterrdquo Journal of Pharmaceutical andBiomedical Analysis vol 75 pp 180ndash185 2013

[29] X Sun X Tian Y Zhang and Y Tang ldquoMolecularly imprintedlayer-coated silica gel particles for selective solid-phase extrac-tion of pefloxacin and enrofloxacin from milk samplesrdquo FoodAnalytical Methods vol 6 no 5 pp 1361ndash1369 2013

[30] H YanM Tian andKH Row ldquoDetermination of enrofloxacinand ciprofloxacin in milk using molecularly imprinted solid-phase extractionrdquo Journal of Separation Science vol 31 no 16-17pp 3015ndash3020 2008

[31] W J Tang T Zhao C H Zhou X J Guan and H XZhang ldquoPreparation of hollow molecular imprinting polymerfor determination of ofloxacin inmilkrdquoAnalyticalMethods vol6 no 10 pp 3309ndash3315 2014

TribologyAdvances in

Hindawiwwwhindawicom Volume 2018


International Journal ofInternational Journal ofPhotoenergy


Journal of

Chemistry


Advances inPhysical Chemistry

Hindawiwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2018

Bioinorganic Chemistry and ApplicationsHindawiwwwhindawicom Volume 2018

SpectroscopyInternational Journal of


Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Medicinal ChemistryInternational Journal of


NanotechnologyHindawiwwwhindawicom Volume 2018

Journal of

Applied ChemistryJournal of



Biochemistry Research International


Enzyme Research


Journal of

SpectroscopyAnalytical ChemistryInternational Journal of


MaterialsJournal of



BioMed Research International Electrochemistry

International Journal of


Na

nom

ate

ria

ls


Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom


the template molecule or structural analogs in a samplemixture [15] MIPs are attractive materials for molecularrecognition due to their low cost simple preparation highstability and good reproducibility under harsh chemical andphysical conditions Consequently MIT has been widelyused in extraction separation [16 17] chemical sensing[18] catalysis [19] and chiral separations [20ndash22] Surfacemolecular imprinting distributes almost all binding sites ona surface with good accessibility by taking some measureswhich facilitates the removal and recombination of templatemolecules This method is therefore particularly suitablefor the preparation of imprinted polymers of biomacro-molecules The distribution of binding sites across the poly-mer surface shortens the adsorption equilibrium time byovercoming the traditional embedding phenomenon [23 24]

The preparation of MIPs using ENR as a templatemolecule has been recently explored in the literature theresulting MIPs would have important implications for theselective detection of ENR in complex matrices Xiao et al[25] prepared FQs imprinted polymers on the surface ofmag-netic carbon nanotubes and simultaneously used a pseudotemplate to achieve fluoroquinolone extraction Additionallywork by He et al [26] firstly attempted to prepare an ENRimprinted material using the magnetic polyhedral oligomericsemi-siloxane composite as a matrix In a similar vein Yan etal [27] thermally initiated polymerization of the monolithiccolumn and use norfloxacin as a pseudo template for ENRthe resulting material demonstrated a high affinity for ENRand norfloxacin in water and successfully afforded the extrac-tion of ENR and norfloxacin from blood samples Despitethese great advancements in the development of MIPs thepreparation of monodisperse ENR imprinted polymers bysurface grafting and the application of the resultant polymersto a real sample analysis have yet to be reported

In this work self-made monodisperse macroporouscross-linked polymeric glycidyl methacrylate-ethylene glycoldimethacrylate (PGMA-EDMA) microspheres are used as thematrix Compared with silica gel and other carriers it is moreresistant to acid and alkaliand has a large number of activegroups on the surface It is an ideal molecularly imprintedcarrier A surface grafting technique was used to prepareenrofloxacin molecular imprinted polymers attached to thesurface of PGMA-EDMA microspheres via MPS modified sitesThe surface structure and the physicochemical properties ofthe polymers were analyzed and used for the detection of fourFQs in milk samples

2 Materials and Method

21 Reagent and Instrument Enrofloxacin (ENR) tetracy-cline (TC) ofloxacin (OFL) chloramphenicol (CAP) gly-cidyl methacrylate (GMA) ethylene glycol dimethacrylate(EDMA) ethylene glycol diglycidyl ether (EGDE) meth-acrylic acid (MAA) ammonium persulfate [(NH4)2S2O8]3-methacryloylpropyl trimethoxysilane (MPS) styrene (St)azobisisobutyronitrile (AIBN) polyvinylpyrrolidone (PVP)cyclohexanol poly(vinyl alcohol) (PVA) dibutyl phthalate(DBP) ethyl alcohol pyridinemethanol acetone acetic acidsodium dodecyl sulfate(SDS)and tetrahydrofuran (THF)

were purchased from Aladdin Reagent (Shanghai China)HPLC grade methanol and acetonitrile were obtained fromSigma (St Louis MO USA) Milk samples were purchasedfrom a local supermarket The polymerization inhibitor wasremoved from the MAA by using a vacuum distillation unitWater was twice distilled prior to use All other reagentswere of analytical grade and usedwithout further purificationunless otherwise specified All solutions prepared for HPLCwere filtered through a 045120583m nylon filter before use

Chromatographywas performed using anLC-20AT chro-matographic system (Shimadzu Japan) equipped with twoLC-20AT pumps and a SPD-20A UVndashVIS detector Sampleswere injected through a Rheodyne 7725 valve Polymersmorphology was characterized by using a JSM-7500F elec-tron scanning microscope (JEOL Co Japan) Elementalanalysis was performed on a VarioEL III elemental analyzer(Elementar Co Germany) Infrared spectra were collectedby using a Fourier transform infrared spectrometer (Shi-madzu Japan) Absorption spectra were collected by using aTU-1810-type ultraviolet spectrophotometer (BeijingGeneralInstrument Co Ltd China) Centrifugation was performedwith a TG16-WS high-speed centrifuge (Centrifuge FactoryChina)

22 Preparation of Monodisperse 119875119866119872119860-119864119863119872119860 MicrospheresMonodisperse polystyrene seeds (PS) were synthesizedaccording to a dispersion polymerization method Themonomer styrene (10 mL) initiator ABIN (02 g) stabilizerPVP (2 g) and anhydrous ethanol (878 mL) were combinedin a 100 mL single-necked flask and sonicated until all of thestyrene ABIN and PVP were dissolved The flask was thenattached to a rotary device equippedwith a heating apparatusPolymerization was carried out at 70∘C over the course of 24h Upon completion of the reaction the solvent was removedby centrifugation and the remaining solids were washed withcopious amounts of ethanol to obtain the desired PS

In a 150 mL single-necked flask GMA (6 mL) ABIN(036 g) EDMA (6 mL) DBP (6 mL) and cyclohexanol (6mL) were combined and sonicated to dissolve completelythen 45 mL distilled water 75 mL 02 SDS solution and35 mL 5 PVA solution were added to the above mixedsolution The reaction mixture was subjected to ultrasonicemulsification for 30 min until complete emulsification ofthe organic phase was achieved The resultant emulsion wasslowly added to a solution of the prepared monodisperse PSwhile the temperature was maintained at 30∘C The reactionmixtureswere stirred for 24 h thendegassed under a nitrogenatmosphere for 20 min and still stirred at 70∘C for additional24 h The solids obtained were washed with water methanoland acetone and then dried in vacuo to yield the productTheporogens were removed by extraction with tetrahydrofuranfor 48 h in a Soxhlet apparatus for products The productswere washed with methanol again and dried in vacuo to yieldthe PGMA-EDMA microspheres

PGMA-EDM (20 g) were suspended in 100 mL of 01 molLsulfuric acid stirred and kept at 60∘C for 12 h Then theproducts were filtered and washed with water until neutraland then dried under vacuum to afford the hydrolyzedPGMA-EDMA microspheres







119876 =(1198620 minus 119862119890) 119881

119898(1)






119870119863 =119876119890119862119890

(2)

119896 =119870119863(119865119876119904)119870119863(119879119862)

(3)

1198961015840 =119870119872119868119875119904119870119873119868119875119904

(4)

120572 =119876119872119868119875119904119876119873119868119875119904

(5)





F

N

OH

O

N

O

N

(ENR)

OH O

OH

NH2

OOOH

HO HCH3 N(CH3)2

OH

(TC)

N N

FO

ON

OH

O

(OFL)

OH

N

OH

HN

Cl Cl

OO

O

(CAP)

minus+










F

NOH

O

N

O

N


C OCH2CHO

CH2

O 01 molL H2SO4 CO

OCH2CH CH2

OH OH

MPS

Si O CH2

CH3

O

H3COH3CO

H3CO

MAA EGDE AIBN



ENR

COH

OCOHO

CHO O

COH

OCOHO

CHO O

PGMA-EDMA

PGMA-EDMAMPS

PS


4000 3500 3000 2500 2000 1500 1000 500

116429553525

1463

1727

Tran

smitt

ance

()

Wavenumber (cm-1)

a

b

c






119876

119862119890= minus119876

119870119889+119876119898119886119909119870119889

(6)


















0 5 10 15 20 25 30 35 40000

002

004

006

008

010Q

Ce (

Lg)

Q (mgg)

(a)

2 4 6 8 10 12 140017

0018

0019

0020

0021

0022

0023

0024

0025

QC

e(L

g)

Q (mgg)

(b)


0 2 4 6 8 100

5

10

15

20

25

30

35

Q (m

gg)

t (min)





00 05 10 15 20 250

5

10

15

20

25

30

35Q

(mg

g)









CAP

TC

ENR0

10

20

30

40

PGMA-EDMAMIPs

PGMA-EDMANIPs

Q (m

gg)

OFL




0 2 4 6 8 10

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

ENR

c

b

a

Time (min)


4 Conclusions


Data Availability


Ethical Approval





200 956 32500 1096 11

C18 100 726 40200 756 32500 783 44






5 826ndash935 [30]






Acknowledgments


References








































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls










119876 =(1198620 minus 119862119890) 119881

119898(1)






119870119863 =119876119890119862119890

(2)

119896 =119870119863(119865119876119904)119870119863(119879119862)

(3)

1198961015840 =119870119872119868119875119904119870119873119868119875119904

(4)

120572 =119876119872119868119875119904119876119873119868119875119904

(5)





F

N

OH

O

N

O

N

(ENR)

OH O

OH

NH2

OOOH

HO HCH3 N(CH3)2

OH

(TC)

N N

FO

ON

OH

O

(OFL)

OH

N

OH

HN

Cl Cl

OO

O

(CAP)

minus+










F

NOH

O

N

O

N


C OCH2CHO

CH2

O 01 molL H2SO4 CO

OCH2CH CH2

OH OH

MPS

Si O CH2

CH3

O

H3COH3CO

H3CO

MAA EGDE AIBN



ENR

COH

OCOHO

CHO O

COH

OCOHO

CHO O

PGMA-EDMA

PGMA-EDMAMPS

PS


4000 3500 3000 2500 2000 1500 1000 500

116429553525

1463

1727

Tran

smitt

ance

()

Wavenumber (cm-1)

a

b

c






119876

119862119890= minus119876

119870119889+119876119898119886119909119870119889

(6)


















0 5 10 15 20 25 30 35 40000

002

004

006

008

010Q

Ce (

Lg)

Q (mgg)

(a)

2 4 6 8 10 12 140017

0018

0019

0020

0021

0022

0023

0024

0025

QC

e(L

g)

Q (mgg)

(b)


0 2 4 6 8 100

5

10

15

20

25

30

35

Q (m

gg)

t (min)





00 05 10 15 20 250

5

10

15

20

25

30

35Q

(mg

g)









CAP

TC

ENR0

10

20

30

40

PGMA-EDMAMIPs

PGMA-EDMANIPs

Q (m

gg)

OFL




0 2 4 6 8 10

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

ENR

c

b

a

Time (min)


4 Conclusions


Data Availability


Ethical Approval





200 956 32500 1096 11

C18 100 726 40200 756 32500 783 44






5 826ndash935 [30]






Acknowledgments


References








































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls





F

N

OH

O

N

O

N

(ENR)

OH O

OH

NH2

OOOH

HO HCH3 N(CH3)2

OH

(TC)

N N

FO

ON

OH

O

(OFL)

OH

N

OH

HN

Cl Cl

OO

O

(CAP)

minus+










F

NOH

O

N

O

N


C OCH2CHO

CH2

O 01 molL H2SO4 CO

OCH2CH CH2

OH OH

MPS

Si O CH2

CH3

O

H3COH3CO

H3CO

MAA EGDE AIBN



ENR

COH

OCOHO

CHO O

COH

OCOHO

CHO O

PGMA-EDMA

PGMA-EDMAMPS

PS


4000 3500 3000 2500 2000 1500 1000 500

116429553525

1463

1727

Tran

smitt

ance

()

Wavenumber (cm-1)

a

b

c






119876

119862119890= minus119876

119870119889+119876119898119886119909119870119889

(6)


















0 5 10 15 20 25 30 35 40000

002

004

006

008

010Q

Ce (

Lg)

Q (mgg)

(a)

2 4 6 8 10 12 140017

0018

0019

0020

0021

0022

0023

0024

0025

QC

e(L

g)

Q (mgg)

(b)


0 2 4 6 8 100

5

10

15

20

25

30

35

Q (m

gg)

t (min)





00 05 10 15 20 250

5

10

15

20

25

30

35Q

(mg

g)









CAP

TC

ENR0

10

20

30

40

PGMA-EDMAMIPs

PGMA-EDMANIPs

Q (m

gg)

OFL




0 2 4 6 8 10

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

ENR

c

b

a

Time (min)


4 Conclusions


Data Availability


Ethical Approval





200 956 32500 1096 11

C18 100 726 40200 756 32500 783 44






5 826ndash935 [30]






Acknowledgments


References








































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls





F

NOH

O

N

O

N


C OCH2CHO

CH2

O 01 molL H2SO4 CO

OCH2CH CH2

OH OH

MPS

Si O CH2

CH3

O

H3COH3CO

H3CO

MAA EGDE AIBN



ENR

COH

OCOHO

CHO O

COH

OCOHO

CHO O

PGMA-EDMA

PGMA-EDMAMPS

PS


4000 3500 3000 2500 2000 1500 1000 500

116429553525

1463

1727

Tran

smitt

ance

()

Wavenumber (cm-1)

a

b

c






119876

119862119890= minus119876

119870119889+119876119898119886119909119870119889

(6)


















0 5 10 15 20 25 30 35 40000

002

004

006

008

010Q

Ce (

Lg)

Q (mgg)

(a)

2 4 6 8 10 12 140017

0018

0019

0020

0021

0022

0023

0024

0025

QC

e(L

g)

Q (mgg)

(b)


0 2 4 6 8 100

5

10

15

20

25

30

35

Q (m

gg)

t (min)





00 05 10 15 20 250

5

10

15

20

25

30

35Q

(mg

g)









CAP

TC

ENR0

10

20

30

40

PGMA-EDMAMIPs

PGMA-EDMANIPs

Q (m

gg)

OFL




0 2 4 6 8 10

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

ENR

c

b

a

Time (min)


4 Conclusions


Data Availability


Ethical Approval





200 956 32500 1096 11

C18 100 726 40200 756 32500 783 44






5 826ndash935 [30]






Acknowledgments


References








































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls



















0 5 10 15 20 25 30 35 40000

002

004

006

008

010Q

Ce (

Lg)

Q (mgg)

(a)

2 4 6 8 10 12 140017

0018

0019

0020

0021

0022

0023

0024

0025

QC

e(L

g)

Q (mgg)

(b)


0 2 4 6 8 100

5

10

15

20

25

30

35

Q (m

gg)

t (min)





00 05 10 15 20 250

5

10

15

20

25

30

35Q

(mg

g)









CAP

TC

ENR0

10

20

30

40

PGMA-EDMAMIPs

PGMA-EDMANIPs

Q (m

gg)

OFL




0 2 4 6 8 10

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

ENR

c

b

a

Time (min)


4 Conclusions


Data Availability


Ethical Approval





200 956 32500 1096 11

C18 100 726 40200 756 32500 783 44






5 826ndash935 [30]






Acknowledgments


References








































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls








CAP

TC

ENR0

10

20

30

40

PGMA-EDMAMIPs

PGMA-EDMANIPs

Q (m

gg)

OFL




0 2 4 6 8 10

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

ENR

c

b

a

Time (min)


4 Conclusions


Data Availability


Ethical Approval





200 956 32500 1096 11

C18 100 726 40200 756 32500 783 44






5 826ndash935 [30]






Acknowledgments


References








































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






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ate

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200 956 32500 1096 11

C18 100 726 40200 756 32500 783 44






5 826ndash935 [30]






Acknowledgments


References








































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls






























Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls




Preparation of Monodisperse Enrofloxacin Molecularly...

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