Determination of arsenic in environmental and biological samples by flow injection inductively coupled plasma mass spectrometry

Abstract

A simple and very inexpensive in situ nebulizer–hydride generator was used with inductively coupled plasma mass spectrometry (ICP-MS) for the determination of arsenic in environmental and biological samples. The application of hydride generation (HG)-ICP-MS alleviated the spectral interferences and sensitivity problems of arsenic determinations encountered when conventional pneumatic nebulization is used for sample introduction. The sample was introduced by flow injection to minimize deposition of solids on the sampling orifice. The arsenic in the sample was reduced to As(III) with L-cysteine before being injected into the HG system. A detection limit of 0.003 ng ml^–1 was obtained for arsenic. The method has been successfully applied to the determination of arsenic in National Research Council of Canada reference materials, CASS-2 (Nearshore Seawater Reference Material for Trace Metals), NASS-3 (Open Ocean Reference Material for Trace Metals) and SLRS-2 (Riverine Water Reference Material for Trace Metals), and in National Institute of Standards and Technology, Standard Reference Material 2670, Toxic Metals in Freeze-Dried Urine. Precision was less than 5% and analysis results were within 6% of the certified values for all determinations.