Trends in certified reference materials for the speciation of trace elements
Résumé
The measurement of the chemical species of elements (instead of the total element concentration) has become an irreversible trend in analytical chemistry. The motivation lies in the fact that the biochemical and geo-chemical behaviour of an element is governed by its species. Quality assurance of the analytical procedures used for speciation analysis requires the analysis of representative reference materials, certified for the relevant species. Up to now the number of existing certified reference materials for trace element species is very limited. The most important ones are environmental CRMs certified for tri-alkyltin compounds, methylmercury, Cr(III)/Cr(VI) and food CRMs certified for arsenic species and methylmercury. Major developments are to be expected in CRMs focussed on environmental problems, including waste treatment, on bioavailability of trace elements in food and on bio-monitoring in occupational health and hygiene. It is, however, unlikely that the producers of CRMs will ever be able to cover all needs. Add to this that many, very active species are notoriously unstable and/or short living and require in-situ analysis. This will lead to different analyti-cal developments, such as analyses in-situ, where the classical concept of CRMs may not stand firm anymore. © Springer-Verlag 2001.