Separation and preconcentration of chromium speciation on chitosan and determination by graphite furnace atomic absorption spectrometry

A novel method for the separation and preconcentration of chromium speciati on with chitosan and determination by graphite furnace atomic spectrometry (GFAAS) has been developed. Adsorption rates of chitosan for Cr-VI and Cr-I II were 98 and 20% at pH 3, respectively. Cr-VI was selectively eluted off from chitosan with 5 ml of 0.1 mol L-1 sodium hydroxide and determined by G FAAS. Accordingly, contents of Cr-III were obtained by the determination of total chromium after Cr-III in water samples had been transformed into Cr- VI. The detection limit (3 sigma, n = 10) for Cr-VI was 0.0468 mug L-1 and the relative standard deviation less than 7.8% at the 0.2 mug L-1 level. Th e method was applied to environmental water samples with recoveries of betw een 92-105%.