ARSENIC SPECIATION IN WATER AND HUMAN URINE BY HPLC-ICP-MS AND HPLC-MO-HG-AAS

Arsenite, arsenate, monomethylarsonate, dimethylarsinate, arsenobetain e, and arsenocholine have been successfully separated in one chromatog raphic run in a mixed mode column, Spherisorb ODS/NH2, using 5.0 mmol liter(-1) phosphate buffer at pH 5.0 as mobile phase and final detecti on by inductively coupled plasma mass spectrometry (ICP-MS) or microwa ve-assisted oven (MO) coupled with hydride generation atomic absorptio n spectrometry (HG-AAS). The detection limits achieved with the HPLC-I CP-MS coupling (0.04-0.28 ng) were about 20 times lower than those ach ieved by HPLC-MO-HG-AAS, which makes it suitable for determining these species at their naturally occurring concentration levels. The chlori de present in the samples was chromatographically separated from the a rsenic species, and the interferent signal from the (ArCl)-Ar-40-Cl-35 formed on the ICP-MS system was insignificant. The proposed methods w ere successfully applied to the determination of six arsenic species i n water and urine (after previous cleanup of the sample). (C) 1998 Aca demic Press.