Determination of arsenic in sea water by sorbent extraction with hydride generation atomic absorption spectrometry

A rapid and sensitive sorbent extraction hydride generation-flow injection analysis atomic absorption spectrometric (HG-FIAS-AAS) method is described for the determination of As(III) and As(V) based upon online preconcentration on a microcolumn packed with activated alumina. In the present procedure these arsenicals are complexed with quinolin-8-ol-5-sulphonic acid from neutral solutions in the flow injection system and adsorbed on the column. The preconcentrated species are eluted with 10% HCl, mixed with 0.5% sodium borohydride and carried to the HG-FIAS cell with a carrier gas flow rate of 75 ml min(-1). The retention efficiency is found to be better than 98% with sensitivity enhancement of 12 and 10 for As(III) and As(V), respectively, for a 20 s preconcentration period. The respective detection limits are 0.05 and 2 ng ml(-1) for As(III) and As(V). The throughput of the samples is found to be 60 h(-1), with a loading time of 20 s. The method has been applied to sea water samples.