Arsenic speciation in biological samples by on-line high performance liquid chromatography-microwave digestionhydride generation-atomic absorption spectrometry

A system capable of the separation of arsenic species by on-line high performance liquid chromatography prior to their online decomposition by microwave digestion, pre-reduction with l-cysteine and analysis by hydride generation-atomic absorption spectrometry has been developed. This approach enables the full speciation of arsenobetaine, monomethylarsonic acid, dimethylarsinic acid and total inorganic arsenic (arsenite + arsenate) in biological samples. Simple modification of the system allows for the determination of the total arsenic content of the sample. In addition quantification of the total reducible arsenic species (arsenite, arsenate, monomethylarsonic acid and dimethylarsinic acid) can be achieved by on-line prereduction-hydride generation-atomic absorption spectrometry. Procedures were validated by analysis of the certified reference materials NRCC DORM-1 and TORT-1 and gave results in good agreement with the certified values.