EVALUATION OF ATOMIC FLUORESCENCE SPECTROMETRY AS A SENSITIVE DETECTION TECHNIQUE FOR ARSENIC SPECIATION

The potential of coupling anion-exchange highperformance liquid chroma tography, hydride generation and atomic fluorescence spectrometry (HPL C-HG-AFS) for arsenic speciation is considered. The effects of hydroch loric acid and sodium tetrahydroborate concentrations on signal-to-bac kground ratio, as well as argon and hydrogen flow rates, were investig ated, Detection limits for arsenite, dimethylarsinic acid (DMA), monom ethylarsonic acid (MMA) and arsenate were 0.17, 0.45, 0.30 and 0.38 mu g l(-1) respectively, using a 20-mu l loop. Linearity ranges were 0,1 -500 ng for As(III) and RIMA (as arsenic), and 0.1-800 ng for DMA and As(V) (as arsenic). Arsenobetaine (AsB) was also determined by introdu cing an on-line photo-oxidation step after the chromatographic separat ion. In this case the Limits of detection and linear ranges for the di fferent species studied were similar to the values obtained previously for As(V), The technique was tested with a human urine reference mate rial and a volunteer's sample. (C) 1998 John Wiley & Sons, Ltd.