DETERMINATION OF ARSENIC COMPOUNDS IN WATER SAMPLES BY LIQUID-CHROMATOGRAPHY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY WITH AN IN-SITU NEBULIZER-HYDRIDE GENERATOR

A preliminary study of an in situ nebulizer-hydride generator as a sam ple introduction device for an inductively coupled plasma mass spectro metry (ICP-MS) system is described. The samples were ionic arsenic com pounds that had undergone chromatographic separation before injection into the hydride generator. L-Cysteine was used instead of potassium i odide as the prereductant. Only mild treatment with nitric acid was ne cessary to obtain a satisfactory hydride efficiency. The sensitivity, detection limits and reproducibility of a liquid chromatographic (LC)- ICP-MS system with a hydride generator were comparable to or better th an an LC-ICP-MS system with conventional pneumatic nebulization or oth er sample introduction techniques. The limits of detection for various arsenic species were in the range 11-51 ng l(-1). The concentrations of various arsenic species in several natural water samples were deter mined.