A dual arsenic speciation system combining liquid chromatographic and purge and trap-gas chromatographic separation with atomic fluorescence spectrometric detection

An arsenic speciation system comprising separation by liquid chromatography (LC) and purge and trap-gas chromatography (PT-GC) interfaced with atomic fluorescence spectrometry (AFS) is described. The system set-up is such that LC and PT-GC may be operated simultaneously, making it a flexible dual arsenic speciation system. The capabilities of this system for quantification of eight arsenic species were investigated. By combining anion and cation columns in the LC section with on-line UV decomposition prior to hydride generation and AFS, it was possible to separate up to six arsenic species with detection limits of ca. 0.5 ng ml−1 As (100 μl injected). Using selective hydride generation prior to PT-GC and AFS, up to four arsenic species with detection limits of ca. 2.5 pg ml−1 (for 100 ml-sample size) could be determined. The speciation power of the dual system for environmental matrices was demonstrated by determination of arsenic species in the mushroom Agaricus bisporus which had been investigated previously by LC-inductively coupled plasma/mass spectrometry. The results of the comparison were in excellent agreement.