ASR-200054372
-
Upload
ferhat-bozduman -
Category
Documents
-
view
15 -
download
1
Transcript of ASR-200054372
This article was downloaded by: [Suleyman Demirel Universitesi]On: 24 November 2011, At: 02:09Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH,UK
Applied Spectroscopy ReviewsPublication details, including instructions forauthors and subscription information:http://www.tandfonline.com/loi/laps20
Recent Advances in MicrowaveInduced Plasma AtomicEmission Spectrometry withOkamoto‐CavityKazuaki Wagatsuma aa Institute for Materials Research, Tohoku University,Sendai, Japan
Available online: 19 Aug 2006
To cite this article: Kazuaki Wagatsuma (2005): Recent Advances in MicrowaveInduced Plasma Atomic Emission Spectrometry with Okamoto‐Cavity, AppliedSpectroscopy Reviews, 40:3, 229-243
To link to this article: http://dx.doi.org/10.1081/ASR-200054372
PLEASE SCROLL DOWN FOR ARTICLE
Full terms and conditions of use: http://www.tandfonline.com/page/terms-and-conditions
This article may be used for research, teaching, and private study purposes.Any substantial or systematic reproduction, redistribution, reselling, loan,sub-licensing, systematic supply, or distribution in any form to anyone isexpressly forbidden.
The publisher does not give any warranty express or implied or make anyrepresentation that the contents will be complete or accurate or up todate. The accuracy of any instructions, formulae, and drug doses should beindependently verified with primary sources. The publisher shall not be liablefor any loss, actions, claims, proceedings, demand, or costs or damages
whatsoever or howsoever caused arising directly or indirectly in connectionwith or arising out of the use of this material.
Dow
nloa
ded
by [
Sule
yman
Dem
irel
Uni
vers
itesi
] at
02:
09 2
4 N
ovem
ber
2011
Recent Advances in Microwave InducedPlasma Atomic Emission Spectrometry
with Okamoto-Cavity
Kazuaki Wagatsuma
Institute for Materials Research, Tohoku University, Sendai, Japan
Abstract: Microwave induced plasmas with an Okamoto-cavity (Okamoto-cavity
MIP) are noted as a new excitation source in atomic emission spectrometry. The
Okamoto-cavity MIP can be sustained with various plasma gases, and can produce
each stable plasma with a high robustness against loading of various types of
samples. For example, the oxygen-containing MIP becomes an effective atomization
and excitation source for direct injection of organic solvents analysis because they
are completely burned in the plasma. In this review, the fundamental structure of the
microwave cavity, the spectrochemical characteristics, and the analytical applications
are summarized from reference papers.
Keywords: Microwave induced plasma, Okamoto cavity, atomic emission spec-
trometry, plasma gas, detection limit, excitation temperature, loading of organic
solvent
INTRODUCTION
Microwave induced plasmas (MIPs) have been known as an excitation source
in atomic emission spectrometry; however, the analytical application appears
only in particular fields such as a detector for gas chromatography (1). The
major reason for this is that conventional MIPs produced by using a
Beenaker cavity (2) or a Surfatron (3) have a limited tolerance to aqueous
aerosol introduction, because such MIPs should be maintained at relatively
Received 25 November 2004, Accepted 2 December 2004
Address correspondence to Kazuaki Wagatsuma, Institute for Materials Research,
Tohoku University, Katahira 2-1-1, Sendai 980-8577, Japan. E-mail: wagatuma@
imr.tohoku.ac.jp
Applied Spectoscopy Reviews, 40: 229–243, 2005
Copyright # Taylor & Francis, Inc.
ISSN 0570-4928 print/1520-569X online
DOI: 10.1081/ASR-200054372
229
Dow
nloa
ded
by [
Sule
yman
Dem
irel
Uni
vers
itesi
] at
02:
09 2
4 N
ovem
ber
2011
low powers (less than 500 W); otherwise, a serious damage of the torch
material may occur. In addition, the conventional MIPs cannot produce an
annular-shaped plasma like an inductively coupled plasma (ICP) because
they have the electric-field distribution yielding the maximum at the center
of their plasmas. These drawbacks have hindered the extensive applications
of MIPs in spite of their specific excitation ability as well as the low-
running cost.
In 1985, Jin et al. reported on a newly designed MIP which allows for
direct introduction of aqueous samples (4). His research group has made
apparatus comprising the MIP torch and a spectrometer for atomic emission
spectrometry (5, 6). In 1990, Okamoto developed a surface-wave-excited
non-resonant cavity for MIP (7). This cavity (Okamoto cavity) (7, 8) has
been expected as a new excitation source in MIP spectrometry because of
the unique feature beyond conventional MIPs. It produces a annular flame-
like plasma where the electric field can be concentrated at the edge of the
plasma, which enables sample aerosols to be easily introduced through the
center channel, as in the case of ICP (7, 8). Furthermore, the plasma can be
maintained at high powers up to 1.5 kW, making this plasma source highly
tolerant to wet aerosol loading. In addition, the Okamoto cavity can be
sustained with various gases, such as nitrogen, air, and helium, without any
modification of the torch design as well as the power supply system (9–13).
The use of nitrogen plasma gas enables the Okamoto cavity to be employed
as an ionization source in mass spectrometry due to its low mass interferences
(14, 15). The nitrogen and helium plasmas with the Okamoto cavity have been
studied also in atomic emission spectrometry. Several researchers have
reported on the excitation characteristics and the analytical performance of
these plasmas, indicating that MIPs with the Okamoto cavity have the
ability enough to be employed for practical applications (10–13,16–26).
These studies are introduced in this review.
PRINCIPLES OF OKAMOTO CAVITY
The apparatus and the basic principle of operation has been described in detail
by Okamoto (7, 8). A brief explanation is described and is cited from
Okamoto’s publications (8).
Figure 1 shows a schematic diagram of the Okamoto cavity comprising a
surface-wave exciter and a discharge tube. The surface-wave exciter consists
of a wave-guide and a mode transformer. The former part works also as an
impedance matching circuit between the microwave source and the
resulting impedance of the surface wave exciter, by reducing the area of the
wave-guide joining to the mode transformer. The latter part consists of an
inner conductor and an outer cylindrical conductor terminated by a front
plate. The surface wave is excited in the gap between the inner and the
outer conductors, where the electric field becomes the maximum and can be
K. Wagatsuma230
Dow
nloa
ded
by [
Sule
yman
Dem
irel
Uni
vers
itesi
] at
02:
09 2
4 N
ovem
ber
2011
coupled with the plasma gas the most efficiently, which enables an annular-
shaped plasma like ICP to be produced. Microwave power is transferred
from a microwave generator running at a frequency of 2.45 GHz to the
surface wave exciter, through a uni-line, a directional coupler, and a three-
stub tuner. Matching in their impedances can be adjusted by using the
three-stub tuner.
The plasma torch comprises two concentric quartz tubes, and has two
paths of the gas flow: one is a tangentially-introduced gas flow which
sustains the plasma itself and the other is introduced through the inner tube
to carry the sample aerosol to the plasma. The detailed design of the torch
was described in Okamoto et al. (7). By selecting the flow rates and the
microwave power appropriately, the resulting plasma can be maintained
without any external cooling. The operating conditions for obtaining the
stable plasmas strongly depend on the kind of the plasma gas (9–13).
Nitrogen or air plasmas are produced by igniting the plasma with argon
under impedance matching conditions best suited to the nitrogen or the air
discharge. The argon plasma can be induced by sparks with a Tesla coil.
The argon flow is replaced by nitrogen or air immediately after the production
of the argon plasma, and then an annular-shaped stable plasma can be
produced at atmospheric-pressure without touching the wall of the outer
tube. Once the stable plasma is formed, the gas flow rates as well as the
microwave power can be varied over relatively wide ranges. In the case of
the nitrogen plasma, the flow rate of the plasma gas can be varied at the
plasma gas flow of 6–15 L/min when the microwave power ranges from
Figure 1. Cross section of the surface-wave exciter and the discharge tube of
Okamoto-cavity. See Okamoto (8).
Recent Advances in MIP Atomic Emission Spectrometry 231
Dow
nloa
ded
by [
Sule
yman
Dem
irel
Uni
vers
itesi
] at
02:
09 2
4 N
ovem
ber
2011
600 to 1000 W. It is possible to optimize the experimental conditions for each
sample as well as each analytical line among these discharge parameters.
CHARACTERISTICS OF OKAMOTO-CAVITY MIP
Excitation Temperature
Okamoto and his co-workers measured the excitation temperature, the rotation
temperature, and the electron number density in the nitrogen MIP (9). The
excitation temperature was estimated from the Boltzmann plot using
Fe I lines (370-nm lines), the rotation temperature was determined from the
band intensity of nitrogen molecule ion at 391.4 nm, and the electron
number density was from the intensity ratio of the Fe I line (252.3 nm) to
the Fe II line (258.6 nm) having a similar excitation energy. Figure 2 shows
variations in the excitation temperature as well as the electron number
density as a function of the microwave power supplied. Both of them
increase with increasing applied microwave power, if other operating con-
ditions are kept constant. At the power of 1.0 kW, the excitation temperature,
the rotation temperature, and the electron number density was estimated to be
5500 K, 5000 K, and 3 � 1013 cm23, respectively. The authors concluded that
the nitrogen MIP was in a local thermodynamic equilibrium (LTE), because
the excitation temperature is similar to the rotation temperature. They also
pointed out that conventional helium MIPs give a large difference between
the excitation and the rotation temperatures due to their non-LTE
Figure 2. Variations in the excitation temperature and the electron number density as
a function of the microwave power. Plasma gas: pure nitrogen; flow rate of the plasma
gas: 10.5 L/min; carrier gas flow rate: 0.62 L/min; observation height: 7.5 mm. See
Ogura et al. (9).
K. Wagatsuma232
Dow
nloa
ded
by [
Sule
yman
Dem
irel
Uni
vers
itesi
] at
02:
09 2
4 N
ovem
ber
2011
characteristics. Okamoto et al. also reported on excitation temperatures of the
Okamoto-cavity MIP using helium and argon: 4900 K for helium and 5500 K
for argon measured under each optimum discharge condition (11).
Zhang and Wagatsuma (19) published on a comparison in the excitation
temperature between the pure nitrogen and the air Okamoto-cavity MIPs, indi-
cating that the excitation temperature of the air-MIP was in the range of 4150–
4750 K when the microwave power was varied from 0.8 to 1.3 kW. The values
were 300–400 K lower than those of the pure nitrogen MIP, which contributed
to the analytical performance of each plasma. Maeda and Wagatsuma (13)
reported on a variation in the excitation temperature when the oxygen
content was varied from 0 to 28 vol.% in nitrogen-oxygen Okamoto-cavity
MIP. As shown in Figure 3, the excitation temperature is reduced with increas-
ing oxygen content. This effect is probably due to the difference in the ioniz-
ation energy and the dissociation energy between nitrogen and oxygen
molecules.
Background Spectra
Okamoto (8) and Ohata (20) published background spectra of the nitrogen
Okamoto-cavity MIP, comprising N2 bands, N2þ bands, and NH band. It
should be noted that the background from these species appears over the wave-
length range of 300–420 nm; however, the OH bands (306 nm system) are very
weak compared to in argon-ICP. Although the nitrogen-oxygen MIP has more
intense backgrounds, such plasma is effective for removing bands originated
from carbon-containing species when introducing organic solvents (10).
Figure 3. Dependence of the excitation temperature on the oxygen content in the
nitrogen-oxygen mixed gas plasma at the microwave power of 1.0 kW. Flow rate of
the plasma gas: 14 L/min; carrier gas flow rate: 0.6 L/min; observation height:
7 mm. See Maeda and Wagatsuma (13).
Recent Advances in MIP Atomic Emission Spectrometry 233
Dow
nloa
ded
by [
Sule
yman
Dem
irel
Uni
vers
itesi
] at
02:
09 2
4 N
ovem
ber
2011
Interference with Easily-Ionizable Elements
Zhang and Wagatsuma (19) investigated the matrix effects of sodium,
calcium, and nitric acid on the emission intensities of a large number of
atomic and ionic lines over a wide rage of excitation energy in the nitrogen
Okamoto-cavity MIP. Figure 4 indicates the variations in the net intensities
of 20 spectral lines when adding 5 mg/mL sodium. Each emission intensity
without sodium is normalized as unity. Most of the atomic lines are
enhanced in the presence of sodium, whereas all of the ionic lines tested are
reduced. These effects decrease with increasing microwave power. The
authors also found that the degree of the matrix effect was strongly
dependent on the excitation energy of the atomic lines as well as the energy
sum (the excitation energyþ the ionization potential) of the ionic lines.
Larger intensity enhancement was observed in the atomic lines having
lower excitation energy, while larger intensity reduction was observed in
the ionic lines having larger energy sum. These phenomena can be
explained from the change in the ionization equilibrium in the MIP which
results from a dominant ionization of sodium. This shows similar behaviour
as the result obtained not in ICP but in flame emission spectrometry.
Figure 4. Effect of 5-mg/mL sodium on the relative emission intensities of various
atomic and ionic lines at three different microwave powers. The spectral lines are
arranged by their excitation energies. Concentration of the analytes: 0.005 mg/mL
for Li, Mg, Ca, Sr, and Ba, 0.1 mg/mL for Al, Cr, Cu, Fe and Mo, and 0.5 mg/mL
for Cd and Zn; plasma gas: pure nitrogen; flow rate of the plasma gas: 13 L/min; carrier
gas flow rate: 0.6 L/min; observation height: 12 mm. See Zhang and Wagatsuma (19).
K. Wagatsuma234
Dow
nloa
ded
by [
Sule
yman
Dem
irel
Uni
vers
itesi
] at
02:
09 2
4 N
ovem
ber
2011
ANALYTICAL APPLICATIONS OF OKAMOTO-CAVITY MIP
Detection Limit
Ohata and Furuta (21) extensively investigated the detection limits of
55 emission lines for 21 elements excited by the nitrogen Okamoto-cavity
MIP, and compared those with the detection limits obtained by using an
argon ICP. The MIP and the ICP were operated under almost the same
plasma conditions and with the same measurement systems. Table 1 shows
Table 1. Comparison in the detection limits between nitrogen-MIP and
argon-ICP (21)
Wavelength
(nm)
Excitation
energy (eV)
Detection
limit N2-MIP
(ng/mL)
Detection
limit Ar-ICP
(ng/mL)
Na I 589.0 2.11 46 5.8
Al I 309.3 4.02 98 21
Al I 396.2 3.14 12 10
Ca I 422.7 2.93 3.7 1.1
Ca II 393.4 3.15 0.38 0.06
V I 437.9 3.13 27 20
V II 292.4 4.63 11 2.0
V II 309.3 4.40 8.8 1.3
Cr I 357.9 3.46 90 7.7
Cr I 429.0 2.89 24 18
Cr II 205.6 6.03 280 4.6
Cr II 267.7 6.18 25 3.3
Ti I 398.2 3.11 120 66
Ti II 334.9 3.74 4.3 0.9
Mo I 390.3 3.17 180 18
Mo II 202.0 6.13 340 6.0
Mn I 279.5 4.44 12 8.6
Mn I 403.1 3.08 18 9.7
Mn II 257.6 4.81 6.9 0.4
Ni I 232.0 5.34 54 14
Ni I 361.9 3.85 23 38
Ni II 221.6 6.63 580 6.8
Ni II 231.6 6.38 150 6.0
Mg I 285.2 4.34 2.2 1.3
Mg II 279.6 4.43 0.60 0.07
Cu I 324.7 3.82 2.3 2.0
Cu II 224.7 8.23 1800 6.9
Fe I 372.0 3.33 79 54
Fe II 259.9 4.77 13 1.6
Fe II 238.2 5.20 40 3.2
Recent Advances in MIP Atomic Emission Spectrometry 235
Dow
nloa
ded
by [
Sule
yman
Dem
irel
Uni
vers
itesi
] at
02:
09 2
4 N
ovem
ber
2011
the data extracted from their analytical results, indicating that the detection
limits obtained with the nitrogen MIP were one to two orders of magnitude
worse than those with the argon ICP.
Yamada and Okamoto (11) reported the determination of non-metal
elements when the helium Okamoto-cavity MIP was employed. It is interest-
ing to detect emission lines of halogen elements such as fluorine and chlorine
because their emission lines requiring high excitation energies cannot be suffi-
ciently excited in argon-ICP (11, 12). Figure 5 shows a typical spectrum in the
wavelength range of 683–692 nm emitted from the helium MIP (12), which
includes several fluorine atomic lines having the excitation energy of about
14.5 eV. The F I 685.6-nm line is the most intense and is thus recommended
as the analytical line for fluorine determination. The detection limit for this
line was estimated to be 150 ng/mL, yielding an improvement by a factor
of 25 over the literature value obtained with a helium Beenekker-cavity MIP.
Hydride Generation
Nakahara and his co-workers published a series of papers describing an
analytical application of the Okamoto-cavity MIP associated with hydride
Figure 5. Spectrum obtained by nebulizing an aqueous solution containing 5-mg/mL
NaF into the helium MIP. Microwave power: 600 W; plasma gas flow rate: 13.5 L/min;
carrier gas flow rate: 0.7 L/min: plasma gas: pure helium. See Okamoto et al. (12).
K. Wagatsuma236
Dow
nloa
ded
by [
Sule
yman
Dem
irel
Uni
vers
itesi
] at
02:
09 2
4 N
ovem
ber
2011
generation technique (16–18, 22–26). The hydride generation technique is
known as an effective sampling method in atomic absorption spectrometry
and ICP spectrometry, enabling hydride-forming elements such as arsenic,
tellurium, antimony, and selenium to be detected more sensitively
compared to the conventional nebulization technique. Because the
Okamoto-cavity MIP has a high tolerance for loading of various forms of
samples, it can be considered that this is suitable for the atomization and exci-
tation source also in the case of hydride introduction. Figure 6 shows a
schematic diagram of their experimental apparatus. The sample introduction
system for hydride generation comprises a reaction path having a peristaltic
pump, a gas-liquid separator, a drying flask, and a nebulizer chamber. In com-
parison, a conventional spraying system with a concentric nebulizer is also
equipped with the nebulizer chamber. An acidified sample solution and an
alkaline tetrahydroborate solution are continuously introduced into the
hydride generator by running the peristaltic pump. After removing water
vapor produced during the hydride generation with the drying flask filled
with concentric sulfuric acid, the analyte elements changed into the hydride
vapor along with excess of hydrogen gas are fed into the MIP by nitrogen
carrier gas through the drain outlet of the nebulizer chamber.
Figure 6. Schematic diagram of the Okamoto-cavity MIP apparatus associated with a
hydride sampling system. A, microwave power supply; B, microwave generator; C1,
C2, tapered waveguide; D, uniline; E, direction coupler; F, three-stub tuner; I, mono-
chromator; J, photomultiplier; N, nitrogen tank; O, argon tank; P, gas controller; Q,
plasma gas; R, carrier gas; S, sample solution for nebulization; T, carrier gas and
sample aerosol or hydride; U, nebulizer; V, nebulizer chamber; X, three-way stop
cock; Y, sample solution for hydride generation; Z, NaBH4 solution; a, peristaltic
pump; b, mixing joint; c, gas-liquid separator; d, drying flask; e: Okamoto-cavity; g,
plasma torch. See Nakahara and Li (16).
Recent Advances in MIP Atomic Emission Spectrometry 237
Dow
nloa
ded
by [
Sule
yman
Dem
irel
Uni
vers
itesi
] at
02:
09 2
4 N
ovem
ber
2011
Under the optimized operation conditions, a comparison of the detection
limit for tellurium was performed between the hydride generation and the con-
ventional nebulization techniques. In case where the Te I 214.281 nm was
employed as the analytical line, the detection limit for the hydride generation
method was 15.0 ng/mL, while that for the solution nebulization method
740 ng/mL, resulting in the improvement in the detection sensitivity by a
factor of 50 (18). The detection limit for the As I 228.821 nm, the Se I
196.026 nm, and the Sb I 231.147 nm was 1.87, 2.99, and 0.86 ng/mL,
respectively, by the same hydride generation method.
More recently, Matsumoto, a member of Nakahara’s research group,
extensively investigated the determination of several elements in steel
samples by the Okamoto-cavity MIP associated with hydride-generation
technique (22–26). Table 2 summarizes the simultaneous determination of
bismuth and tellurium in three standard reference materials of steel.
The obtained analytical values were in good agreement with the certified
values (26).
Introduction of Organic Solvent
The direct aspiration of organic solvents into the plasma for emission analysis
can be useful for the rapid determination. The air-ICP (27–30), the air-MIP
(31–34), and the air capacitively coupled microwave plasma (35) have
been investigated for both aqueous and organic sample aerosol introduction.
Generally, the use of plasmas containing oxygen should be suitable to direct
organic solvent introduction due to the combustion. This promises a useful
application of this plasma source as a detector in liquid chromatography.
Further, the air-MIP may be used in the direct analysis of the organic
extract, in the case where solvent extraction is performed to separate minor
analyte elements from the matrix (27, 34).
Maeda and Wagatsuma (36) reported on the emission characteristics of
ethanol solution excited from the nitrogen-oxygen mixed gas MIPs.
Figure 7 indicates a variation in the excitation temperature as a function of
Table 2. Simultaneous determination of bismuth and tellurium in steel samples by
Okamoto-cavity nitrogen MIP with hydride generation (26)
Certified values (mg/g)a Obtained values (mg/g)
Sample Bismuth Tellurium Bismuth Tellurium
SS 192–1 0.098 0.031 0.0932 + 0.0007 0.0351 + 0.0004
ISS 193–1 0.034 0.026 0.0393 + 0.0004 0.0284 + 0.0005
ISS 195–1 0.032 0.042 0.0358 + 0.0003 0.0450 + 0.0008
aThe mean + standard deviation, based on five replicate determination.
K. Wagatsuma238
Dow
nloa
ded
by [
Sule
yman
Dem
irel
Uni
vers
itesi
] at
02:
09 2
4 N
ovem
ber
2011
the ethanol content in the aspirated solution. The excitation temperatures were
estimated from Boltzmann plots using iron atomic lines ranging in 367–
368 nm. The excitation temperature is almost independent of the ethanol
content (about 4750 K) when nitrogen-28% oxygen is used as the plasma
gas. It is assumed that the excitation conditions are little changed even by
introducing 80 vol% ethanol into the plasma, probably because of complete
combustion of ethanol.
The same authors reported on direct analysis of 4-methyl-2-pentanone
(MIBK), which was frequently employed as an solvent extraction reagent to
remove minor elements from the iron matrix in steel samples, by using the
nitrogen-oxygen Okamoto-cavity MIP (37). Figure 8 shows the intensity
changes of the Swan band of C2 radical (516.5 nm, 0–0 band head) (38)
with increasing oxygen content in the nitrogen-oxygen mixed gas plasma,
when MIBK is introduced into the plasma. The band spectra originated from
C2 radical could not be observed if the oxygen content is more than 21 vol%.
It implies that carbon atoms from MIBK can be fully oxidized in
the oxygen-containing plasma and therefore few carbon radicals are in the
plasma. It is likely to say that the nitrogen-oxygen mixed gas MIP with the
Okamoto cavity has a high tolerance to loading of organic solvents. The
resultant plasma can be kept stable even when the MIBK solution is introduced.
SUMMARY
The Okamoto-cavity MIP has several noticeable features: a high robustness
against loading of various types of samples and a good matching for
Figure 7. Variation in the excitation temperature as a function of the ethanol content
when the nitrogen-28 vol.% oxygen mixed gas MIP is employed. Microwave power:
1.0 kW; total flow rate of the plasma gas: 14 L/min; carrier gas flow rate: 0.7 L/min;
observation height: 13 mm. See Maeda and Wagatsuma (36).
Recent Advances in MIP Atomic Emission Spectrometry 239
Dow
nloa
ded
by [
Sule
yman
Dem
irel
Uni
vers
itesi
] at
02:
09 2
4 N
ovem
ber
2011
various plasma gases. In the case of nebulization of aqueous samples, the
detection limits for the nitrogen Okamoto-cavity MIP are inferior to those
for a conventional argon ICP. However, wider and specified applications of
the Okamoto-cavity MIP can be expected; for example, direct analysis of
organic solvents in the oxygen-containing MIP or detection of non-metallic
elements in the helium MIP. This plasma would have a potential when
various kinds of samples must be analyzed in atomic emission spectrometry.
ACKNOWLEDGMENT
The author gratefully acknowledges Dr. Y. Okamoto for many useful sugges-
tions for the MIP instruments.
REFERENCES
1. Broekaert, J.A.C. (2001) Analytical Atomic Spectrometry with Flames andPlasmas; Wiley-VCH Verlag: Weinheim.
Figure 8. Variation in the intensities of the C2 Swan band (516.5 nm) as a function of
the oxygen content in the nitrogen-oxygen mixed gas MIP when MIBK is directly
introduced. Microwave power: 1.0 kW; total flow rate of the plasma gas: 14 L/min;
carrier gas flow rate: 0.7 L/min; observation height: 13 mm.
K. Wagatsuma240
Dow
nloa
ded
by [
Sule
yman
Dem
irel
Uni
vers
itesi
] at
02:
09 2
4 N
ovem
ber
2011
2. Beenakker, C.I.M. (1976) Cavity for microwave-induced plasmas operated in
helium and argon at atmospheric-pressure. Spectrochim. Acta, 31B: 483–486.
3. Hubert, J., Moisan, M., and Ricard, A. (1979) New microwave plasma at
atmospheric-pressure. Spectrochim. Acta, 34B: 1–10.
4. Yang, W., Zhang, H., Yu, A., and Jin, Q. (2000) Microwave plasma torch
analytical atomic spectrometry. Microchem. J., 66: 147–170.
5. Jin, Q., Zhu, C., Borer, M.W., and Hieftje, G.M. (1991) A microwave plasma torch
assembly for atomic emission-spectrometry. Spectrochim. Acta, 46B: 417–430.
6. Jin, Q., Wang, F., Zhu, C., Chambers, D.M., and Hieftje, G.M. (1990) Atomic
emission detector for gas-chromatography and supercritical fluid chromatography.
J. Anal. At. Spectrom., 5: 487–494.
7. Okamoto, Y., Yasuda, M., and Murayama, S. (1990) High-power microwave-
induced plasma source for trace element analysis. Jpn. J. Appl. Phys., 29:
L670–672.
8. Okamoto, Y. (1991) Annular-shaped microwave-induced nitrogen plasma at
atmospheric-pressure for emission-spectrometry of solutions. Anal. Sci., 7:
283–288.
9. Ogura, K., Yamada, M., Sato, Y., and Okamoto, Y. (1997) Excitation temperature
in high-power nitrogen microwave-induced plasma at atmospheric pressure. Appl.
Spectrosc., 51: 1496–1499.
10. Zhang, Z. and Wagatsuma, K. (2002) Comparison of the analytical performance of
high-powered, microwave-induced air plasma and nitrogen plasma atomic
emission spectrometry. J. Anal. At. Spectrom., 17: 699–703.
11. Yamada, H. and Okamoto, Y. (2001) Characteristics of a high-power microwave-
induced helium plasma at atmospheric pressure for the determination of nonmetals
in aqueous solution. Appl. Spectrosc., 55: 114–119.
12. Okamoto, Y., Murohashi, H., and Wake, S. (2001) Detection of aqueous fluoride
with a high-power microwave-induced helium plasma at atmospheric pressure.
Anal. Sci., 17: 967–970.
13. Maeda, T. and Wagatsuma, K. (2004) Emission characteristics of high-powered
microwave induced plasma optical emission spectrometry by using nitrogen-
oxygen mixture gas. Microchem. J., 76: 53–60.
14. Okamoto, Y. (1990) Analytical technology for trace elements using atmospheric
pressure plasma. Trans. IEE Japan, 110: 759–766.
15. Okamoto, Y. (1994) High-sensitivity microwave-induced plasma mass spec-
trometry for trace element analysis. J. Anal. At. Spectrom., 9: 745–749.
16. Nakahara, T. and Li, Y. (1998) Determination of trace amounts of antimony in
pure copper by high-power nitrogen microwave-induced plasma atomic
emission spectrometry with hydride generation. J. Anal. At. Spectrom., 13:
401–405.
17. Nakahara, T., Li, Y., Takeuchi, H., and Futamura, M. (1999) Sensitive determi-
nation of arsenic and selenium in steels by high power nitrogen microwave
induced plasma atomic emission spectrometry coupled with hydride generation
technique. Testu-to-Hagane, 85: 97–101.
18. Nakahara, T. (2002) High power nitrogen microwave induced plasma for the deter-
mination of some trace elements in steels by atomic emission spectrometry with
hydride generation technique. ISIJ Int., 42: s114–s121.
19. Zhang, Z. and Wagatsuma, K. (2002) Matrix effects of easily ionizable elements
and nitric acid in high-power microwave-induced nitrogen plasma atomic
emission spectrometry. Spectrochim. Acta, 57B: 1247–1257.
Recent Advances in MIP Atomic Emission Spectrometry 241
Dow
nloa
ded
by [
Sule
yman
Dem
irel
Uni
vers
itesi
] at
02:
09 2
4 N
ovem
ber
2011
20. Ohata, M. and Furuta, N. (1997) Spatial characterization of emission intensities
and temperatures of a high power nitrogen microwave-induced plasma. J. Anal.
At. Spectrom., 12: 341–347.
21. Ohata, M. and Furuta, N. (1998) Evaluation of the detection capability of a high
power nitrogen microwave-induced plasma for both atomic emission and mass
spectrometry. J. Anal. At. Spectrom., 13: 447–453.22. Matsumoto, A., Oheda, A., and Nakahara, T. (2001) Sensitive determination of
antimony in steels by high power nitrogen microwave induced plasma atomic
emission spectrometry coupled with hydride generation technique. Tetsu-to-
Hagane, 87: 449–453.
23. Matsumoto, A., Oheda, A., and Nakahara, T. (2002) Simultaneous determination
of arsenic and antimony in steels and pure coppers by high power nitrogen
microwave induced plasma atomic emission spectrometry coupled with hydride
generation technique. Tetsu-to-Hagane, 88: 270–276.
24. Matsumoto, A., Oheda, A., and Nakahara, T. (2003) Simultaneous determinationof arsenic, bismuth and antimony in steels by high power nitrogen microwave
induced plasma atomic emission spectrometry coupled with hydride generation
method. Tetsu-to-Hagane, 89: 587–592.
25. Matsumoto, A., Shiozaki, T., and Nakahara, T. (2003) Determination of bismuth in
steels by high power nitrogen microwave induced plasma atomic emission spec-
trometry coupled with hydride generation technique. Tetsu-to-Hagane, 89:
953–957.
26. Matsumoto, A., Shiozaki, T., and Nakahara, T. (2004) Simultaneous determination
of bismuth and tellurium in steels by high power nitrogen microwave inducedplasma atomic emission spectrometry coupled with the hydride generation
technique. Anal. Bioanal. Chem., 379: 90–95.
27. Meyer, G.A. (1987) Determination of metals in xylene by inductively coupled air
plasma emission-spectrometry. Spectrochim. Acta, 42B: 201–206.
28. Meyer, G.A. and Thompson, M.D. (1985) Determination of trace-element
detection limits in air and oxygen inductively coupled plasmas. Spectrochim.
Acta, 40B: 195–207.
29. Meyer, G.A. and Barnes, R.M. (1985) Analytical inductively coupled nitrogen and
air plasmas. Spectrochim. Acta, 40B: 893–905.30. Kovacic, N., Meyer, G.A., Liu, K.L., and Barnes, R.M. (1985) Diagnostics in an air
inductively coupled plasma. Spectrochim. Acta, 40B: 943–954.
31. Urh, J.J. and Carnahan, J.W. (1985) Determination of metals in aqueous-solution
by direct nebulization into an air microwave induced plasma. Anal. Chem., 57:
1253–1255.
32. Urh, J.J. and Carnahan, J.W. (1986) Analytical figures of merit and interelement
effects with air and nitrogen microwave-induced plasmas. Appl. Spectrosc., 40:
877–883.
33. Zhang, Y.K., Hanamura, S., and Winefordner, J.D. (1985) Evaluation of
microwave-induced air-plasma as an excitation source. Appl. Spectrosc., 39:226–230.
34. Michlewicz, K.G., Urh, J.J., and Carnahan, J.W. (1985) A microwave induced
plasma system for the maintenance of moderate power plasmas of helium,
argon, nitrogen and air. Spectrochim. Acta, 40B: 493–499.
35. Seelig, M., Bings, N.H., and Broekaert, J.A.C. (1998) Use of a capacitively
coupled microwave plasma (CMP) with Ar, N2 and air as working gases for
atomic spectrometric elemental determinations in aqueous solutions and oils.
Fresenius J. Anal. Chem., 360: 161–166.
K. Wagatsuma242
Dow
nloa
ded
by [
Sule
yman
Dem
irel
Uni
vers
itesi
] at
02:
09 2
4 N
ovem
ber
2011
36. Maeda, T. and Wagatsuma, K. (2005) Direct loading of ethanol solution into high-power nitrogen-oxygen mixed gas microwave induced plasma and the emissioncharacteristics. Spectrochim. Acta, 60B: 81–87.
37. Maeda, T. and Wagatsuma, K. Emission characteristics of Okamoto-cavitymicrowave-induced plasma in direct introduction of organic solvents and theanalytical application to MIBK extraction from iron-matrix samples. Tetsu-to-Hagane, 91: 35–41.
38. Pearse, R.W.B. and Gaydon, A.G. (1965) The Identification of Molecular Spectra;Chapman & Hall, Ltd: London.
Recent Advances in MIP Atomic Emission Spectrometry 243
Dow
nloa
ded
by [
Sule
yman
Dem
irel
Uni
vers
itesi
] at
02:
09 2
4 N
ovem
ber
2011