2006 Volume 22 Issue 4 Pages 571-574
A rapid differential pulse adsorptive stripping voltammetric method has been developed for the ultra-trace determination of chromium using 2,2′-bipyridine. The base electrolyte used is 0.1 M NH4Cl (pH 6.0). The peak current was found to increase substantially with the addition of nitrite ions. A well-defined peak was observed at -1.3 V. Parameters, like concentration of the ligand, concentration of nitrite ion, accumulation potential, accumulation time, rest period, drop size, scan rate, pulse amplitude etc. have been optimized. Under the optimum conditions, the 3 σ detection limit was found to be 0.02 ppb (3.8 × 10-10 M). The method is highly selective and sensitive, and has been applied to the determination of Cr(VI) in spiked water, effluents and ore samples.