Critical review perspective: elemental speciation analysis methods in environmental chemistry - moving towards methodological integration

Abstract

Environmental context. Elemental speciation defines mobility, accumulation behaviour and toxicity of elements in the environment. Environmental processes are then modelled using species information. Hence, it is important for environmental chemists to rely on unequivocal, precise and accurate analytical data for the identification and quantification of elemental species.Abstract. We review the application of speciation analysis used in environmental chemistry studies to gain information about the molecular diversity of elements in various environmental compartments. The review focuses on three major analytical methodologies: electrochemical, X-ray absorption spectroscopy, and methods that couple chromatography with mass spectrometric detection. In particular, the review aims to highlight the advantages and disadvantages of the three methods, and to demonstrate that both the chemistry of the element and the nature of the environmental compartment determine the choice of the preferred analytical technique. We demonstrate that these two factors can lead to techniquedependent shortcomings that contribute to the current gaps in knowledge of elemental speciation in the environment. In order to fill those gaps, multi-method approaches are urgently needed. Finally, we present a selection of recent studies that exhibit the potential to use complementary techniques to overcome method-dependent limitations in order to reduce ambiguities and to gain more confidence in the assignment of the molecular structure of elements in environmental samples. Jörg Feldmann received his Ph.D. in Environmental Analytical Chemistry at University of Essen (Germany). He is the recipient of the Prize of the University of Essen and the Feodor Lynen Award (Alexander von Humboldt Foundation). After two years at the University of British Columbia (Canada), he became lecturer in 1997 at the University of Aberdeen (Scotland), where he progressed to a Chair in 2004. He is a member of the Environmental Chemistry Advisory Board and has published more than 100 scientific papers mainly on element speciation analysis in environmental and biological systems. The main focus of his research is on the use of hyphenated techniques for elemental and molecular mass spectrometry.Pascal Salaün is an analytical and environmental chemist interested in the physico-chemical processes influencing the biogeochemical cycling of trace elements. He is specialised in the development of electrochemical sensors for the detection and speciation of metals and metalloids in natural systems. Currently, his research focuses on the use of solid microelectrodes, their application for on-site/in-situ monitoring and complexation studies together with the development of metallic nanostructures for electroanalytical purposes. He obtained a 5 years research fellowship in 2007 focusing on arsenic speciation in fresh/marine waters and in biological systems. Enzo Lombi received a Ph.D. in agricultural chemistry

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