Analytical chemists play the key role in the generation and interpretation of analytical data. Requirements for the chemist to provide this data for an increasing diversity of elements in more and more complicated matrices have grown almost exponentially over the last thirty years and there is every reason to believe that this requirement for growth will even speed up over the next thirty. How is it then possible to keep pace with or even ahead of this trend?

Inductively-Coupled Plasma Mass Spectrometry is now over a decade old, the landmark paper being published by Houk et al in 1980. Traditionally ICP-MS was a solution-based technique, relating back to its origins in association with ICP-AES. However, unlike ICP-AES, the versatility of ICP-MS with its potential of isotope quantification and ultra-low detection limits has acted as the catalyst for its association with perhaps the most diverse range of interface techniques that has ever been associated with any base analytical instrument. This gives ICP-MS the potential of being used in perhaps the widest range of inorganic analytical applications of any instrument currently available.

In the Chemistry Centre (WA) ICP-MS occupies both a work horse and research niche. Our traditional customer, the geologist demands routine analytical data for over fifty elements at concentrations in the low parts per million range and in rock types varying from carbonates through silicates to sulphides. The use of ICP-MS to provide lead and copper isotope data on a pre-screening basis prior to more accurate TIMS analysis is also well utilised. Environmental and forensic chemical applications test the detection limits of the technique with requirements for parts per trillion data, often because only extremely small sample quantities are available for analysis. It is perhaps in the clinical and forensic areas, however, that the true elegance of ICP-MS is highlighted. Coupling the technique to preconcentration devices such as ion-exchange columns and separation techniques such as liquid chromatographs facilitates the analysis of organo-metallic compounds and heralds, I feel, our potential to understand for the first time the true role of metals in biological systems and their impact on the ecosystem. Application of graphite furnace and total consumption ICP-MS in clinical, pharmaceutical, mineralogical and environmental areas makes it possible for the analyst to use microlitre sample volumes and accurately determine femtogram quantities of metals.

All the applications so far discussed require sample presentation in solution, however, it is perhaps the use of ICP-MS in association with solid sampling techniques that offers the most exciting application of the technology. Of the solid sampling techniques available, laser ablation (LA) offers the greatest challenge and opportunity. UV, IR and Excimer lasers have all been used to produce a microparticulate cloud of the sample matrix under investigation and all with varying degrees of success. A major problem is that the push for more discrete sampling does not go hand in hand with reproducibility and to date only a limited number of sample matrices have been analysed successfully by LA-ICP-MS. Quantitative data is difficult to obtain as sample coupling, orientation of crystalline materials, colour and laser focussing have all conspired to cause problems. However, the new generation of lasers have facilitated a quantum leap forward in overcoming some of these problems. Data are, however, still variable and because of this, in our laboratory, we have adopted the view that as all our samples are composed of a cocktail of elements then perhaps the association of these elements is the key to identification of sample provenance. This approach has been extremely successful in our forensic investigations, particularly for gold and diamond theft, cannabis crop location, and in mineral exploration initiatives.

In this presentation I will attempt to overview the diverse application of ICP-MS in modern inorganic analytical chemistry illustrating all aspects with practical examples.