Determination of arsenic speciation in sulfidic waters by Ion Chromatography Hydride-Generation Atomic Fluorescence Spectrometry (IC-HG-AFS)

A method for the analysis of arsenic species in aqueous sulfide samples is presented. The method uses an ion chromatography system connected with a Hydride-Generation Atomic Fluorescence Spectrometer (IC-HG-AFS). With this method inorganic AsIII and AsV species in water samples can be analyzed, including arsenite ( H n As III O 3 n − 3 ) , thioarsenite ( H n As III S 3 n − 3 ) , arsenate ( H n As V O 4 n − 3 ) , monothioarsenate ( H n As V SO 3 n − 3 ) , dithioarsenate ( H n As V S 2 O 2 n − 3 ) , trithioarsenate ( H n As V S 3 O n − 3 ) and tetrathioarsenate ( H n As V S 4 n − 3 ) . The peak identification and retention times were determined based on standard analysis of the various arsenic compounds. The analytical detection limit was ~1–3 µg L−1 (LOD), depending on the quality of the baseline. This low detection limit makes this method also applicable to discriminate between waters meeting the drinking water standard of max. 10 µg L−1 As, and waters that do not meet this standard. The new method was successfully applied for on-site determination of arsenic species in natural sulfidic waters, in which seven species were unambiguously identified.