Simultaneous determination of toxic arsenic and chromium species in water samples by ion chromatography inductively coupled plasma mass spectrometry

A method based on ion chromatography in conjunction with inductively coupled plasma mass spectrometry is presented for simultaneous determination of toxic chromium and arsenic species: Cr(VI), As(III) and As(V) using KNO3 at pH 9.8 as eluent. Cr(III), dimethylarsinate, monomethylarsonate, arsenobetaine and arsenocholine did not interfere with the analysis, since Cr(III) was eliminated before analysis and As species were separated from the analytes. The advantages and disadvantages of gradient and isocratic elution in trace speciation analysis by ion chromatography are discussed. With the method described, Cr(VI), As(III) and As(V) could be analyzed at a concentration level of 0.5 mu g/l. An application of the proposed method is presented for waste water and drinking water analysis. (C) 1997 Elsevier Science B.V.