Abstract An analytical procedure for determination of As() and As() in soils using sequential extraction combined with flow injection (FI) hydride generation atomic fluorescence spectrometry (HG-AFS) was presented. The soils were sequentially extracted by water, 0.6mol/L KH2PO4 solution , 1%(v/v) HCl solution and 1%(w/v) NaOH solution . The arsenite (As()) in extract was analyzed by HG-AFS in the medium of 0.1 mol/L citric acid solution , then the total arsenic in extract was determined by HG-AFS using on-line reduction of arsenate with L-cysteine . The concentration of arsenate (As()) was calculated by the difference . The optimum conditions of and determination were studied in detail . The detection limit (3) for As() and As() were 0.11 and 0.07 ug/L,respectively. The relative standard deviation (R.S.D.) was 1.43%(n=11) at the 10 ug/L As level. The method was applied in the detemination of As() and As() of real soils and the recoveries of As() and As() were in the range of 89.3-118 and 80.4-111%,respectively. AF-610D2色譜－原子熒光聯(lián)用儀