A DUAL ARSENIC SPECIATION SYSTEM COMBINING LIQUID-CHROMATOGRAPHIC ANDPURGE-AND-TRAP GAS-CHROMATOGRAPHIC SEPARATION WITH ATOMIC FLUORESCENCE SPECTROMETRIC DETECTION

An arsenic speciation system comprising separation by liquid chromatog raphy (LC) and purge and trap-gas chromatography (PT-GC) interfaced wi th atomic fluorescence spectrometry (AFS) is described. The system set -up is such that LC and PT-GC may be operated simultaneously, making i t 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 U V decomposition prior to hydride generation and AFS, it was possible t o separate up to six arsenic species with detection limits of ca. 0.5 ng ml(-1) As (100 mu l injected), Using selective hydride generation p rior to PT-GC and AFS, up to four arsenic species with detection limit s of ca. 2.5 pg ml(-1) (for 100 mi-sample size) could be determined. T he speciation power of the dual system for environmental matrices was demonstrated by determination of arsenic species in the mushroom Agari cus bisporus which had been investigated previously by LC-inductively coupled plasma/mass spectrometry. The results of the comparison were i n excellent agreement. (C) 1998 Elsevier Science B.V.