Preconcentration of total chromium on Dowex 50W-X8 resin loaded with 2-amino-benzenethiol

Application of Dowex 50W-X8 loaded with 2-amino-benzenethiol for preconcentration of total chromium (Cr(VI) and Cr(III)) in water samples and subsequent determination by inductively coupled plasma-atomic emission spectrometry was studied. The reagent 2-amino-benzenethiol loaded onto the resin effectively reduced Cr( VI) to Cr( III) and total chromium ( both Cr( VI) and Cr( III)) formed chelate complex with the reagent in the Cr( III) valence state. Experimental parameters such as preconcentration time, solution flow rates, pH, and concentration of the eluent were optimized. The method has been applied for the determination of total chromium in seawater samples in the range of 0.1 - 200 mu g L-1. A detection limit of 0.3 mu g L-1 was achieved, and the relative standard deviation was about 5%.