Arsenic speciation in biological samples using the couplings HPLC-UV-HG-AAS and HPLC-UV-HG-AFS

A speciation procedure for arsenobetaine (AsB), arsenite (As-III), dimethyl arsinic acid (DMA), monomethylarsonic acid (MMA) and arsenate (As-v) based on the couplings HPLC-HG-AFS and HPLC-UV-HG-AFS has been developed and resu lts compared with HPLC-HG-AAS and HPLC-UV-HG-AAS. AFS detection improves th e performance of these couplings, being the detection limits about twenty t imes lower (from 0.06 to 0.14 mu g l(-1) for AFS against 1.1 to 3.9 mu g l( -1) for AAS). The linear range extends from 0.25 to 8000 mu g l(-1) for AFS in contrast to 5 to 500 mu g l(-1) for AAS. This approach has been applied to the arsenic speciation in biological tissues (certified material TORT-1 and fresh bivalve tissues) in which arsenobetaine was the main species fou nd. Extraction of the species has been carried out using repetitive extract ions with methanol and methanol/water (1:1) mixtures being the later more s uitable for quantitative recovery.