Advances in Atomic Spectroscopy (eBook)

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2002 | 1. Auflage
438 Seiten
Elsevier Science (Verlag)
978-0-08-055083-1 (ISBN)

Infos

"Volume 7 continues the tradition of previous volumes in this series by presenting cutting-edge and current advances in atomic spectroscopy. This volume focuses on the application of atomic spectroscopy particularly ICPMS, with an emphasis in the area of clinical and biological samples

New techniques such as double focusing and field-flow fractionation ICP-MS are presented. Other areas such as laser induced breakdown spectrometry and new applications of graphite furnace AAS are included. A major theme of many of the chapters is speciation, which is the hottest topic in elemental determination at present.

?Focuses on cutting-edge advances in atomic spectroscopy
?Contributors are leaders in their fields
?Can be used in conjunction with the other books in the series or as a stand-alone title"

Inhalt

Front Cover 1
Advances in Atomic Spectroscopy 4
Copyright Page 5
Table of Contents 6
Preface 14
Contents and Contributors to Volumes 1-6 in the Series 16
Short Biography of Contributors to Volume 7 20
Abstract of Chapters in Volume 7 28
Chapter 1. Use of atomic spectrometry (ICP-MS) in the clinical laboratory 34
1. Introduction 34
2. Atomic spectrometry techniques in the clinical laboratory 36
3. Inductively coupled plasma mass spectrometry 44
4. Determination of trace element concentrations in body fluids and tissues 48
5. Stable isotopes tracers: a tool for research and diagnosis 53
6. Speciation 62
7. Reference methods and reference materials for trace element analysis 63
References 63
Chapter 2. New developments in hydride generation-atomic spectrometry 86
1. Introduction 86
2. Novel hydride generation 87
3. Advances of methods of atomization 101
4. Chemical interferences in liquid phase and pre-reduction 107
5. Hyphenated techniques 113
6. Applications 120
7. Conclusion 136
References 137
Chapter 3. Analysis of biological materials by double focusing-inductively coupled plasma-mass spectrometry (DF-ICP-MS) 150
1. Introduction 150
2. Instrumentation 154
3. Elemental analysis of biological samples 162
4. Isotope ratio measurements 183
5. Trace metal speciation 191
References 205
Chapter 4. Field-flow fractionation-inductively coupled plasma-mass spectrometry 212
1. Introduction 212
2. General overview 215
3. Selected applications 234
4. Comparison with SEC 237
5. Atomic spectrometry as element specific detection 238
6. On-channel flow-fff preconcentration with atomic spectrometric detection 248
7. Conclusion and future trends 256
Acknowledgements 258
References 259
Chapter 5. Slurry sample introduction in atomic spectrometry : application in clinical and biological analysis 270
1. Introduction 270
2. Overview and nomenclature 271
3. Slurry sample introduction 275
4. Analytical figures of merit 284
5. Practical applications of slurry sample introduction 288
6. Conclusions 289
7. Suggestions for future studies 290
Acknowledgements 291
References 291
Chapter 6. Application of laser-induced breakdown spectrometry in biological and clinical samples 320
1. Introduction 320
2. Fundamental studies 323
3. Excitation temperatures and electron densities 44
4. Spectral and analytical characteristics of LIBS 343
5. Instrumentation 347
6. Applications 359
Conclusion 381
References 381
Chapter 7. Application of graphite furnace atomic absorption spectrometry in biological and clinical samples 394
1. Introduction 394
References 436
Index 438

Textauszug

Chapter 2

New developments in hydride generation - atomic spectrometry

Hiroaki Tao1; Taketoshi Nakahara2    1 - National Institute of Advanced Industrial Science and Technology, 16-1, Onogawa, Tsukuba, Ibaraki, 305-8569, JAPAN,
2 - Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Sakai, Osaka 599-8531, JAPAN.

1 INTRODUCTION

For some time, the generation of volatile hydrides of As, Sb, Bi, Se, Te, Ge, Sn and Pb has been used for sample introduction in atomic spectrometry. Since the work by Holak [1], numerous investigations have been carried out, and the hydride generation techniques may be considered to be mature. However, in recent years, there has been more fundamental research on new hydride generation methods, such as electrochemical hydride generation, vesicular hydride generation, and the production of unstable hydrides such as those of cadmium and copper. Mechanisms of chemical interferences in solution, and atomization interferences in flames, have been studied in depth, and methods to overcome these interferences have been proposed. For application to biological and clinical samples, elemental speciation has become a steady trend since it is essential to identify and quantify individual chemical species, in order to know the biological and toxicological effects of the elements. Hydride generation has been used for improving the detection limits of hyphenated methods, which combine separation methods, such as high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE), with element-specific detection methods such as atomic absorption spectrometry (AAS) and inductively coupled plasma mass spectrometry (ICP-MS). Many investigations concerning the on-line photooxidation or microwave-assisted digestion of organoarsenic or organoselenium compounds prior to hydride generation have expanded the applicability of hydride generation to a variety of compounds. Since 1993 the number of papers on hydride generation in atomic spectrometry has exceeded 600. Hence, it seems almost impossible to cover all aspects of hydride generation. For more comprehensive information, the following recent reviews and books are available: Dĕdina and Tsalev [2], Tsalev [3], Yan and Ni [4], Nakahara [5] and Matusiewicz and Sturgeon [6] for hydride generation, Caroli [7], Welz [8], Burguera and Burguera [9], Szpunar-Łobińska et al. [10], Muñoz et al. [11] and Dauchy et al. [12] for speciation.

In this chapter, a presentation is made of novel developments in hydride generation, chemical intereferences and their elimination, instrumental developments for elemental speciation, and practical applications to biological and clinical samples, all of which have occurred since a previous review in this series [13].

2 NOVEL HYDRIDE GENERATION

2.1 Electrochemical hydride generation

One major shortcoming associated with use of the sodium borohydride (NaBH4)–acid reduction technique for hydride generation (HG) is its susceptibility to interferences from transition metals. This system is dependent on the oxidation state of the analyte, and NaBH4 is also a potential source of contamination, which may limit detection power. It is expensive and is unstable in solution form, which generally necessitates daily preparation of fresh reagent. Electrochemical HG (EcHG) is a possible alternative to the NaBH4 reaction. It offers the potential advantage of requiring fewer reagents, therefore less chance exists for sample contamination by traces of analyte in the reagents. The generation of arsenic hydride by electrochemical reduction was first reported by Sand and Hackford in 1904 [14]. Rigin and coworkers demonstrated the use of a batch type EcHG for the determination of As and Sn, and found this method to be remarkably free from chemical interferences [15,16]. In recent years, a number of investigations on a new flow type EcHG have been done to realize the above-mentioned potential advantage of EcHG. Selected examples of recent research on EcHG are given in Table 1.

Table 1

Electrochemical Hydride Generation

As(III), Se(IV), Sb(III)

AAS

3.1 ng ml- 1 for As, 4.0 ng ml- 1 for Se for 100 μl sample volume

vitreous carbon / 1 M H2SO4 / ion exchange membrane

polyester film, mangrove leaves, medicine

Vitreous carbon, Pt and Ag-Hg were tested as cathode material and H2SO4, HClO4, HNO3 and HCl were tested as electrolyte. Experiments with Pt (hydrogen overpotential: 0.10 V), vitreous carbon (0.82 V) and Ag-Hg (1.42 V) cathodes showed that a cathode with a higher overpotential gave a higher signal. Interference from transition metals varied with the cathode material.

17

As(III), As(V), Se(IV), Se(VI)

AAS, ICP-AES

3.1 ng ml- 1 for As, 4.0 ng ml- 1 for Se for 100 μl sample volume

Pt / diluted H2SO4 or HCl / ion exchange membrane (Nafion)

NIST SRM 363, 365 alloy steel

Anolyte: 2 M H2SO4. As(V) and Se(VI) gave no signal response. No depression of the analyte signal is observed even at concentrations of the interfering ions (Ni and Co) of up to 10000 μg ml- 1.

18

As(III), As(V), Se(IV), Se(VI), Sb(III), phenylarsi ne oxide

AAS, ICP-AES

0.7 ng ml- 1 for As, 3 ng ml- 1 for Se

Pt, Ag, Pd, Pb / 1 M H2SO4, NaOH, H3PO4 / porous glass frit

NIST SRM 1648 urban particulate matter, 1646 estuarine sediment

Cell was operated in the voltage regulated mode. 22 V for As and Se; 18 V for Sb. No significant difference between the effectiveness of Pt, Ag and Pd cathodes for AsH3 generation. Pd gave the best results for H2Se. The Pb cathode gave the largest signal for SbH3, but corroded quickly in IM H2SO4 above 18 V. Efficiencies of HG were as follows: As(III), 50-98%; As(V), 10% of that of As(III); phenylarsine oxide, 25% of that of As(III); Se(IV), 65-98%; Se(VI), 0%; Sb(V), 0%. Se(VI) and Sb(V) gave no signal under any conditions.

19

As(III), As(V)

QTAAS

0.4 ng ml- 1 for 1 ml sample volume

fibrious carbon / 1 M H2SO4 / frites made of glass-wool or silicagel and potassium silicate

water, medicine

Several cathode materials were tested and efficiency of AsH3 generation increases in the following order: Pt < Ag < Cu-cuttings < Cu-powder < fibrious carbon, Pb. Hydride was generated from only As(III) but not from As(V). On-line pre-reduction of As(V) was performed with L-cysteine.

22

Sb(III), Sb(V)

in situ trapping/E TAAS

20 pg ml- 1 for 2 ml sample volume

Pb / 0.3 - 2.4 M HCl 0.35 - 0.55 M H2SO4 / ion exchange membrane (Raipore 1010 or Neosepta CM-1)

NRCC SLRS-2 and 3 river water, NASS-4 seawater

Cell was operated in the constant-current mode (150 mA cm- 2). Efficiencies of SbH3 production from Sb(III) with Pb, pyrolytic graphite and Pt cathgode were 90%, < 45% and 0%, respectively. When Cl2 could be visibly detected in anolyte solution, siganal would drop dramatically. To reduce the Cl2 and to recover the signal, hydroxylamine hydrochloride was added to the anolyte. Efficiency of SbH3 generation from Sb(III) or Sb(V) was same.

23

As(III), Sb(III), Se(IV)

in situ trapping/E TAAS

-

Pb, pyrolytic graphite, vitreous carbon, Pt / 1.2 – 7 M HCl or 0.54 M H2SO4 / ion exchange membrane (Raipore 100 or Neosepta CM-1)

-

Mechanism of direct interference or memory interference by Cu2 + and Ni2 + was described.

24

As(III), As(V), Sc(IV), Se(VI), ΜΜΑA, DMAA, AB, AC

in situ trapping/E TAAS

As: 84 pg ml- 1 for 1 ml sample volume. Se: 7.5 pg ml- 1 for 10 ml sample volume.

Pb / 0.3 - 2.4 M HCl or 0.18 - 1.44 M H2SO4 / ion exchange membrane (Raipore 1010 or Neosepta CM-1)

NASS-4, CASS-3 seawater

Pb, Zn and Pt were evaluated as cathode materials for the production of H2Se. The efficiencies with Pb and Zn were about 60% and that with Pt was 0%. The reproducibility of H2Se production with Zn cathode was very poor. With Pb cathode, the efficiencies of HG from various species were as follows: As(III), 86%; As(V), 73-86%; MMAA, 86%; DMAA, 56%; AB and AC, 0%; Se(IV), 60%; Se(VI), 30%. Pre-reduction of As(V) and Se(VI) was performed with the addition of 1% cysteine and boiling with HCl, respectively.

25

As(III)

in situ trapping/E TAAS

15 pg ml- 1 for 200 μl sample volume

Pb(10 × 100 mm, thickness 1 mm) / 0.1 M H2SO4 / ion exchange membrane (Nafion type NAF117, Dupont)

-

Current density:...

Produkt-Details

• Erscheint lt. Verlag: 14.11.2002
• Mitarbeit: Herausgeber (Serie): J. Sneddon
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Chemie ► Analytische Chemie
• Themenwelt: Naturwissenschaften ► Geowissenschaften ► Mineralogie / Paläontologie
• Themenwelt: Naturwissenschaften ► Physik / Astronomie ► Elektrodynamik
• Themenwelt: Technik
• ISBN-10: 0-08-055083-5 / 0080550835
• ISBN-13: 978-0-08-055083-1 / 9780080550831