Arsenic speciation by ion chromatography with inductively coupled plasma mass spectrometric detection

Abstract

Four As compounds were successfully separated and detected by single-column ion chromatography with inductively coupled plasma (ICP) mass spectrometric detection. The mass spectral interferent ArCl⁺ was reduced by chromatographically resolving chloride from the negatively charged arsenic species. Determination of four As species was investigated in urine, club soda and wine. Detection limits of 0.16 ng of As^III, 0.26 ng of As^v, 0.073 ng of dimethylarsinic acid (DMA) and 0.18 ng of methylarsonic acid (MMA) in wine were obtained. Sensitivity was further improved by using an He—Ar mixed gas ICP as the ionization source. However, the intensity of the ArCl⁺ interference was also increased using this plasma. Detection limits of 0.063 ng of As^III, 0.037 ng of As^v, 0.032 ng of DMA and 0.080 ng of MMA in club soda were achieved using the He—Ar plasma source. Similar limits of detection were found in urine and wine.