Analysis of antimony species – lessons learnt from more than two decades of environmental research

Abstract

Environmental contextThe environmental behaviour and toxicological effects of antimony depend strongly on the specific form of the element, and thus methods have been developed for measuring the various forms of antimony. These methods, applicable to quite clean samples, often fail when applied to more complex environmental samples. We discuss some of the pitfalls in determining environmental antimony forms and the resulting risk of getting the bigger picture wrong regarding antimony pollution. AbstractThe major findings of ~20 years of research on the analysis of antimony species in environmental samples are summarised in this paper. The complex chemistry of antimonite (SbIII) as well as of antimonate (SbV) plays a major role in chromatographic speciation of these species. For simple matrices, like surface or ground-water samples, antimony redox speciation has become a routine analysis and is robust and highly reproducible, if certain aspects are taken into consideration. These aspects are the formation of a stable complex of SbIII and complex formation kinetics. Then the antimony redox species can be separated on an anion-exchange column and detected with a suitable element detector (inductively coupled plasma–mass spectrometry (ICP-MS) or hydride generation–atomic fluorescence spectrometry (HG-AFS)) for trace analysis. The influence of complexing agents in the sample matrix, or in the eluent, on the formation of SbIII and SbV complexes and possible corruption of chromatography is discussed. This ability of antimony to form rather stable complexes also increases the risk of artefact formation during extraction of solid samples.