Arsenic speciation analysis: A review with an emphasis on chromatographic separations

Abstract More than 100 different arsenic species of diverse characteristics are present in the environment and biological systems. The identification and quantification of individual arsenic species are critical to understanding the distribution, environmental fate and behaviour, metabolism, and toxicity of arsenic species. This review summarizes sample preparation, separation, detection, and method validation for arsenic speciation analysis. An emphasis is placed on chromatographic separation techniques, relating the physicochemical properties of arsenic species to their efficient separation. Anion exchange, cation exchange, reversed-phase, ion pair, and size exclusion chromatography are useful to separate various arsenic species. Recent research has explored hydrophilic interaction liquid chromatography (HILIC), multiple separation mechanisms, and testing of fluorophenyl and graphene oxide stationary phases for the separation of arsenic species. Sample preparation, extraction of arsenic species, recovery of arsenic species from separation columns, and method validation are discussed in light of their importance to the integrity and accuracy of speciation analysis.