Atomic spectrometry update. Atomic mass spectrometry

Abstract

This Update is part of a series of annual reviews which cover various aspects of analytical atomic spectrometry. The series of mass spectrometry reviews was initiated in 1988 under the auspices of Allan Ure, who made a major contribution to the development of the ASU reviews and their predecessor, the Annual Reports in Analytical Atomic Spectrometry. After relinquishing the helm of this MS review, Allan continued to oversee its development by acting as an assessor until shortly before his death in December 2005. Details of Allan’s life and his contributions to atomic spectroscopy can be found in his obituary. Allan will be missed by many in the analytical atomic spectrometry community.

We welcome Randy Parrish to the writing team and value his in-depth knowledge of high-precision isotope ratio analysis. This year’s review follows the same format as last year’s. Although an attempt is made to consider all relevant refereed papers, conference abstracts, reports, book chapters and patents for inclusion, the content of the review is highly selective. The selection of papers is based on criteria applied to focus sharply on the most significant developments in instrumentation and methodology or improved understanding of the fundamental phenomena involved in the MS process. The increasing importance of speciation and the blurring of boundaries between atomic and molecular MS require a high degree of judgement to be made in considering papers for inclusion. The main ruling criterion for all speciation papers is that the work should involve or be intended for the study of natural systems. For example, the study of synthetic metal clusters is generally not included whereas the determination of organometallic compounds in environmental samples is.

Applications of atomic MS are not covered in this Update and readers are referred to the Updates on Industrial Analysis: Metals, Chemicals and Advanced Materials, Environmental Analysis and Clinical and Biological Materials, Food and Beverages.

Throughout this review, the term molecular ion will be restricted to denote only the positive or negative radical ion formed by removal or capture, respectively, of an electron. In contrast, addition of a proton or cation to a neutral molecule gives molecular adduct ions. Deprotonated molecules are considered as fragments.

Although reproducibility or precision is a key figure of merit in MS, there is no agreed format for quoting it. The reader can assume that values of precision given in this Update as a percentage correspond to the RSD unless otherwise specified. For isotope ratios, however, values of precision are generally given as the SD of a permil value.

It is a widespread phenomenon that analytical techniques in general and MS in particular spawn a large number of abbreviations and acronyms. A glossary of all abbreviations used in this Update appears at the end of the review. Most abbreviations are not defined in the text but those which are unlikely to be commonly known are defined in the text when used first and again in the glossary.

The developments highlighted in this review indicate the very wide area of applications for which atomic MS can be used. From the measurement of very low isotopic abundances to the measurement of element concentrations at any scale, from bulk analysis to depth profiling and localized analysis, there is likely to be an MS procedure which can provide analytical performance competitive with any other technique. Two substantial reviews highlighted the important role of MS in areas of considerable importance. The excellent review by Becker on recent developments in isotope analysis focused on methodological and instrumental developments, novel approaches and applications using different MS techniques. The list of techniques reviewed by Hou et al. for application in nuclear forensics was dominated by MS methods. The two reviews emphasised the dominant role that ICP-MS now plays in these areas of research.