Determination of urinary arsenic by solvent extraction and electrothermal atomic absorption spectrometry. A comparison with directly coupled high-performance liquid chromatography–inductively coupled plasma mass spectrometry

Abstract

A modified method for the determination of arsenic in urine using solvent extraction with toluene and ETAAS is described. The urine samples were acidified with HCl and reduced with KI followed by a stripping step from the organic solvent with a 1% HNO₃ solution. Only inorganic, mono- and dimethylated arsenic species, correlated with occupational exposure, were determined while trimethylated species, such as arsenobetaine, arising from seafood consumption, were not extracted. The results were compared with those obtained by HPLC–ICP-MS. A good agreement between the two different determinations was found and the solvent extraction method was considered suitable for a correct evaluation of occupational exposure to inorganic arsenic.