Preconcentration of chromium (III) and speciation of chromium by electrothermal atomic absorption spectrometry using cellulose adsorbent

A simple and sensitive method has been developed for species selective determination of chromium(III) and chromium(VI) in water by electrothermal atomic absorption spectrometry. The procedure is based on selective absorption of Cr(III) on a cellulose micro column (pH 11, 0.5 mol L-1 NaCl). Total chromium was subsequently determined after appropriate reduction of Cr(VI) to Cr(III). Recoveries of more than 97% were found. A concentration factor of 100 was achieved. The relative standard deviations (n=10) at the 40 ng L-1 level for chromium(III) and chromium(VI) were 2.3% and 1.8% and corresponding limits of detection (based on 3 sigma) were 1.8 ng L-1 and 5.1 ng L-1, respectively. No interference effects have been observed from other investigated species and the method has been successfully applied to natural water samples.