Handbook of Inductively Coupled Plasma Spectrometry

Handbook of Inductively Coupled Plasma Spectrometry

Handbook of Inductively Coupled Plasma Spectrometry Second Edition MICHAEL THOMPSON, BSc, PhD, ARCS, CChem., FRSC Department of Chemistry Birkbeck College University of London J. NICHOLAS WALSH, BSc, PhD Department of Geology Royal Holloway and Bedford New College University of London with additional invited chapters from S.J. Walton and G.E.M. Hall Blackie Glasgow and London Published in the USA by Chapman and Hall New York

Blackie and Son Ltd Bishopbriggs, Glasgow G64 2NZ 7 Leicester Place, London WC2H 7BP Published in the USA by Chapman and Hall a division of Routledge, Chapman and Hall, Inc. 29 West 35th Street, New York, NY 10001-2291 1989 Blackie & Son Ltd Softcover reprint of the hardcover 1st edition 1989 First published 1983 Reprinted 1984, 1985, 1986 This edition 1989 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, recording or otherwise, without prior permission of the Publishers. British Library Cataloguing in Publication Data Thompson, Michael, 1942- Handbook of inductively coupled plasma spectrometry. -2nd ed. I. Chemical analysis. Inductively coupled plasma emission spectroscopy I. Title II. Walsh, J. Nicholas (John Nicholas) 543'.0858 ISBN-13: 978-1-4612-8037-8 e-isbn: 978-1-4613-0697-9 DOl: 10.1007/978-1-4613-0697-9 Library of Congress Cataloging-in-Publication Data Thompson, Michael, Ph.D. Handbook of inductively coupled plasma spectrometry. "A complete revision with additional invited chapters from S.J. Walton and G.E.M. Hall." Bibliography: p. Includes index. \. Plasma spectroscopy. I. Walsh, J.N. (John Nicholas) II. Title. QD96.P62T48 1988 543'.0858 88-20270 Phototypesetting by Thomson Press (India) Limited, New Delhi

Preface The first edition of our Handbook was written in 1983. In the preface to the first edition we noted the rapid development of inductively coupled plasma atomic emission spectrometry and its considerable potential for elemental analysis. The intervening five years have seen a substantial growth in ICP applications; much has happened and this is an appropriate time to present a revised edition. The basic approach of the book remains the same. This is a handbook, addressed to the user of the technique who seeks direct, practical advice. A concise summary of the technique is attempted. Detailed, theoretical treatment of the background to the method is not covered. We have, however, thoroughly revised much of the text, and new chapters have been added. These reflect the changes and progress in recent years. We are grateful to Mr Stephen Walton, Dr Gwendy Hall and London and Scandinavian Metallurgical Co. Ltd for their contributions. Chapter 3 (Instrumentation) has been rewritten by Mr Walton, the new Chapter on ICP-mass spectrometry has been written by Dr Hall, and London and Scandinavian provided much of the information for the chapter on metals analysis by ICP-AES. These chapters have been integrated into the book, and a conscious effort has been made to retain the unity of style within the book. New material has been added elsewhere in the book, archaeological materials are considered, pre concentration methods and chemometrics covered more fully. Other sections of the Handbook have stood the test of time and remain much as before. The chapter on 'ICP and the future' has been omitted-the future is with us now. It is our intention that this Handbook will provide an introduction to ICP spectrometry for those using the technique in routine analytical applications. It is designed to present general background information on ICP-AES analysis for those who need to familiarize themselves with the reality and the potential of the technique. The book brings together a systematic collection of information on the background and operation of the ICP. It also provides detailed methods for those involved in routine analysis. In our revision of the book we have tried to expand its usefulness to cover a greater range of areas of application. We hope that it will be both a laboratory manual and a general reference text. We should like to acknowledge our considerable debt to all those friends and colleagues who have contributed to this book, directly or v

vi PREFACE indirectly, by way of material assistance, collaboration, technical discussion or simply tolerating us while we were writing. One of us (JNW) is indebted to the Natural Environment Research Council, the University of London and Philips for financial support, and to Jan Barker and Alison Warren for their support and assistance.

Contents 1 Introduction 1 1.1 Preliminary-purpose and scope of book 1 1.1.1 The ICP as a spectroscopic source 1 1.1.2 Applications of the ICP 3 1.1.3 Simplicity of the ICP technique 3 1.1.4 The literature of ICP-AES 4 1.2 Historic development of ICP spectrometry 5 1.3 Background to quantitative ICP analysis 7 1.3.1 Sample introduction (nebulization) 8 1.3.2 Sample excitation system 9 1.3.3 Analysis and quantification of emission spectrum 12 1.4 Range of determinable elements in geological materials 14 2 Analytical characteristics 16 2.1 Introduction 16 2.2 Simultaneous analysis 19 2.2.1 Compromise operating conditions 19 2.3 Sequential analysis ICP system 23 2.4 Detection limits 24 2.5 Calibration range oflcp-aes 25 2.6 Interferences 26 2.6.1 Spectral overlaps 27 2.6.2 Stray light interference 29 2.6.3 Matrix effect 30 2.7 Precision and accuracy 32 2.7.1 Chemometric improvements to data quality 34 2.8 Experimental considerations 37 2.8.1 Solution volumes and sample weights 37 2.8.2 Number of elements determined in liquid samples 38 2.8.3 Number of elements determined in solid samples 39 2.9 The injection of organic liquids into an ICP 40 3 Instrumentation for ICP-AES 43 3.1 Introduction 43 3.2 Spectrometers 45 3.2.1 General requirements 45 3.2.2 Simultaneous spectrometers 47 3.2.3 Sequential spectrometers 55 3.2.4 Combined simultaneous/sequential spectrometers 59 3.3 Plasma torches 59 3.3.1 Nomenclature 59 3.3.2 The Greenfield torch 60 3.3.3 The Fassel torch 60 3.3.4 The Minitorch 64 3.3.5 Torch maintenance 65 3.4 Nebulizer systems 66 3.4.1 Introduction 66 3.4.2 Concentric pneumatic nebulizers 66 vii

viii CONTENTS 3.4.3 Cross-flow nebulizers 72 3.4.4 Babington-type nebulizers 74 3.4.5 Frit-type nebulizers 75 3.4.6 Ultrasonic nebulizers 76 3.4.7 Direct nebulization 77 3.4.8 Spray chambers 77 3.5 Radiofrequency generators and source 80 3.6 Electronics, computers and software 81 3.6.1 Software requirements 82 3.6.2 Trends 83 3.7 Fourier transform spectrometers 83 3.8 ICP-atomic fluorescence spectrometry 85 3.9 Direct current plasmas (DCP) 86 3.10 Microwave plasmas (MIP) 88 3.11 Choice of an ICP system 88 3.11.1 ICP-AES in relation to AAS 88 3.11.2 ICP-AES and X-ray fluorescence 89 3.11.3 ICP-AES and DCP emission spectrometry 90 3.11.4 ICP-AES and ICP-mass spectrometry 90 3.11.5 ICP-AES and other excitation methods 9 I 3.11.6 Evaluation of an ICP-AES system 92 4 Silicate rock analysis 93 4.1 Dissolution methods for silicates 93 4.1.1 Introduction 93 4.1.2 Fusion dissolution methods 93 4.1.3 Hydrofluoric acid dissolution methods-open evaporation 95 4.1.4 Hydrofluoric acid dissolution methods-closed digestion 96 4.2 Instrument calibration 99 4.3 Major element determinations 100 4.4 Trace element analysis 105 4.5 Rare earth element determinations 120 4.5.1 Introduction 120 4.5.2 Dissolution procedure 122 4.5.3 REE separation 124 4.5.4 REE spectral lines 125 4.5.5 Evaluation of results 127 5 Multielement applications of ICPS in applied geochemistry 130 5.1 The nature and evolution of applied geochemistry 130 5.1.1 Introduction 130 5.2 General aspects of applied geochemical analysis 131 5.2.1 Analytical requirements in applied geochemistry 131 5.2.2 Analytical quality control procedures 133 5.3 ICP instrumentation in relation to the requirements of applied geochemistry 137 5.3.1 Introduction 137 5.3.2 Translational interference effects 138 5.3.3 Rotational interference effects 14 I 5.3.4 Other instrumental constraints in multielement analysis 145 5.4 Decomposition procedures in applied geochemical analysis 147 5.4.1 Introduction 147 5.4.2 General aspects of large-batch analysis 150 5.4.3 Decomposition with nitric acid and perchloric acid 155 5.4.4 Decomposition with hydrofluoric acid, nitric acid and perchloric acid (test tube version) 156

CONTENTS ~ 6 Gas phase sample injection 161 6.1 The development of gas phase injection methods 161 6.2 Methodology of the hydride injection system 164 6.2.1 Equipment 164 6.2.2 Operating conditions 166 6.2.3 Performance of the hydride generation/icp system 167 6.2.4 Interference effects and their avoidance 170 6.2.5 Arsenic speciation methods 173 6.3 Applications of the hydride injection system 173 6.3.1 General introduction 173 6.3.2 Traces of arsenic, antimony and bismuth in soils and sediments 174 6.3.3 Traces of arsenic, antimony and bismuth in plant materials 176 6.3.4 Trace concentrations of selenium in soils and sediments 177 6.3.5 The determination of trace concentrations of arsenic, antimony, bismuth, selenium and tellurium in waters 178 6.3.6 The determination of tin in rock, soils and sediments 180 7 Injection methods for solid samples 183 7.1 Introduction to solid sample injection methods 183 7.2 Sample injection following electrothermal vaporization 184 7.3 Direct sample injection from a graphite rod 187 7.4 Discrete sample injection by means of laser ablation 188 7.4.1 General introduction 188 7.4.2 The Lasertrace system 190 7.4.3 The LMAIO laser-icp microprobe system 191 7.5 Nebulization of slurries 199 8 Water analysis by ICP-AES 201 8.1 Introduction 20 I 8.2 General aspects of water analysis 203 8.2.1 Sampling 203 8.2.2 Filtration 203 8.2.3 Storage 204 8.2.4 Stabilization 204 8.2.5 Avoidance of contamination 204 8.3 Direct water analysis by ICP-AES 205 8.3.1 Pneumatic nebulizers 205 8.3.2 Alternative nebulizers 207 8.3.3 Gas phase injection 208 8.3.4 Electrothermal vaporization and other discrete methods 208 8.4 Water analysis with preconcentration 209 8.4.1 Evaporation methods 209 8.4.2 Mixed-bed ion exchange method 210 8.4.3 Selective ion exchange methods 210 8.4.4 Solvent extraction methods 210 8.4.5 A chelation-solvent extraction procedure 211 8.4.6 Coprecipitation methods 213 9 The analysis of environmental materials by ICP-AES 215 9.1 Introduction 2 I 5 9.2 Air analysis 216 9.2.1 Volatile contaminants 216 9.2.2 Particle contaminants 217 9.3 Sewage sludge 219

x CONTENTS 9.4 Domestic dust, road dust and industrial dust 220 9.4.1 Domestic dusts 220 9.4.2 Road dusts 220 9.4.3 Industrial dusts 223 9.5 Domestic and industrial refuse 223 9.6 The analysis of animal and plant tissues 224 9.6.1 General introduction 224 9.6.2 Sample decomposition of biological materials 227 9.6.3 Destruction of organic matter in plant and animal tissue with perchloric acid-nitric acid mixtures 230 10 The analysis of archaeological materials by ICP-AES 232 10.1 Introduction 232 10.2 Archaeological materials 233 10.2.1 Analysis of flints 233 10.2.2 Pottery and clay analysis 235 10.2.3 Analysis of bricks, tiles, glazes, etc. 236 10.2.4 Analysis of metals 236 10.2.5 Analysis of slags and ores 237 11 Inductively coupled plasma mass spectrometry 238 ILl Instrumentation 238 11.2 Optimization 242 11.3 Interferences 243 11.3.1 Spectral interferences 243 11.3.2 Non-spectral interferences 246 11.4 Calibration strategies 247 11.4.1 External 248 11.4.2 Isotope dilution 249 11.4.3 Standard additions 251 1l.5 Applications of ICP-MS with sample introduction by nebulization 251 11.5.1 Elemental analysis of solubilized geological samples 252 11.5.2 Isotope ratio measurements 257 11.5.3 Analysis of waters 260 11.6 Other modes of sample introduction 262 11.6.1 Electrothermal vaporization (ETV) 262 11.6.2 Direct sample insertion device (DSID) 265 11.6.3 Laser ablation of solids 265 11.6.4 Arc nebulization (solid sampling) 267 11.6.5 Slurry nebulization (solid sampling) 267 11.7 Future directions 268 12 Analysis of metals by ICP-AES 270 12.1 Introduction 271 12.1.1 Instrument calibration 272 12.1.2 Internal standards 272 12.1.3 Sample preparation and dissolution 273 12.2 Analysis of iron and steel 274 12.2.1 Spectral lines 274 12.2.2 Sample dissolution 274 12.3 Analysis of other metals 276 12.3.1 Virgin aluminium program 277 12.3.2 Titanium-boron-aluminium program 278 12.3.3 Zirconium-aluminium program 279 12.3.4 Chromium program 280 12.3.5 Chrome carbon program 281

CONTENTS 12.3.6 Nickel-cobalt ailoy program 12.3.7 Ferro-boron program 12.3.8 Nickel-boron program 12.3.9 Copper base program 12.3.10 Stellite program 12.3.1 I Manganese tablet program 12.3. I 2 Ferro-aluminium program Appendix 1 Safety Appendix 2 Manufacturers of ICP systems and accessories References Index xi 281 281 283 283 284 285 285 287 291 294 311