Industrial Analysis: Metals Chemicals and Advanced Materials (1995)

This Atomic Spectrometry Update is tbe latest in an annual series appearing under the title of 'Industrial Analysis'. The structure of the review is broadly the same as in previous years. It is evident from this year's literature that atomic spectrometric techniques are now beginning to develop in areas beyond the traditional remit of elemental compositional analysis. The instrumentation and methodology is now available to solve many of the most difficult problems in quantitative analysis, albeit at a substantial cost (e.g., magnetic sector MS instrumentation). Consequently much of the research effort reported has gone into either improving the limitations of particular instrument types or to broaden the application horizons of existing techniques. In the case of the former, methods for preconcentration of analytes and separation or removal of matrix components using column chromatography or extraction techniques predominate, particularly in the analysis of metals, nuclear materials and refractories. The improvements in sensitivity and freedom from chemical and spectral interferences which this type of approach confers can be applied to most of the spectroscopies of relevance with some benefit. In ICP-MS, the use of such techniques in conjunction with isotope dilution methodology has been successful in normalizing recoveries and in improving accuracy and precision. The now familiar and increasingly popular sample pretreatments involving HPLC- and GC-coupled techniques with plasma spectometers for speciation are, of course, related to the ion exchange/chelation resin separation methods, but add value in providing molecule-and ion-specific information. However, the multi-element capability of ICP-MS and ICP-AES in chromatographic speciation applications is hardly used at all, perhaps indicating a limitation in current thinking. New frontiers are opening up in the use of GPC and HLPC for molecular mass characterization via elemental detection, and in the notion of the combination of MS with soft plasma ionization (e.g., ICP or GD) to obtain molecular information in addition to elemental composition. The advent of electrospray MS is also of great interest in the identification of the valence state and even complexes present in solution, and it may be that the classic separation between inorganic and organic spectroscopic techniques is coming to an end. The direct analysis of solids remains a subject of much activity, and the ultimate goal of quantitative two- and three-dimensional compositional mapping by lateral and depth profiling gets a little closer each year, via techniques such as GD and laser sampling for AES and MS and non-destructively by SIMS and X-ray microfluorescence. Total-reflection XRF too, is clearly becoming a powerful tool for the surface characterization of semiconductors, and advances in optics and detector technologies have increased the range of conventional XRF in light element detection of relevance in this area. It is often difficult to see the major advances in a given field because of the experience of daily contact with the subject. However, after 10 years of Atomic Spectometry Updates, it is gratifying to look back and see so many of the ideas which were being formulated a decade ago find their way into routine industrial application. This reviewer looks forward to the next decade with enthusiasm !