Catalytic Adsorptive Stripping Voltammetric Procedure for Determination of Total Chromium in Environmental Materials

Abstract

AbstractA sensitive catalytic adsorptive stripping voltammetric procedure for determination of traces of total chromium in environmental samples is reported. The method is based on the preconcentration of a Cr(III)H2DTPA complex by adsorption at the HMDE from an acetate buffer solution at the potential −1.0 V vs. Ag/AgCl. Total chromium was determined as Cr(III) after reduction of Cr(VI) to Cr(III) by NaHSO3. In order to stabilize the signal of Cr(III) the measurements were performed at 5 °C. The calibration graph for chromium for an accumulation time of 60 s was linear in the range from 5×10−10 to 5×10−8 mol L−1. The relative standard deviation for a chromium concentration of 1×10−8 mol L−1 was 3.9% (n=5). The detection limit for accumulation time of 60 s was about 8×10−11 mol L−1. The validation of the procedure was performed by the analysis of the certified reference materials.