Determination of As(III) and As(V) in water samples by flow injection online sorption preconcentration coupled to hydride generation atomic fluorescence spectrometry

摘要

A method was developed for the determination of arsenite [As(III)] and arsenate [As(V)] in water samples using flow injection online sorption coupled with hydride generation atomic fluorescence spectrometry (HG-AFS) using a cigarette filter as the sorbent. Selective determination of As(III) was achieved through online formation and retention of the pyrrolidine dithiocarbamate arsenic complex on the cigarette filter, but As(V) which did not form complexes was discarded. After reducing As(V) to As(III) using L-cysteine, total arsenic was determined by HG-AFS. The concentration of As(V) was calculated by the difference between As(III) and total arsenic. The analytes were eluted from the sorbent using 1.68 mol L~(-1) HCl. With consumption of 22 mL of the sample solution, the enrichment factor of As(III) was 25.6. The detection limits (3a/k) and the relative standard deviation for 11 replicate determinations of 1.0 ng mL~(-1) As(III) were found to be 7.4 pg mL~(-1) and 2.6%, respectively.