DETERMINATION OF CHROMIUM IN SEDIMENT BY ADSORPTIVE STRIPPING VOLTAMMETRY

Abstract

     Square-wave adsorptive stripping voltammetry (SqW-AdSV) with bismuth film electrode (BiFE) was applied to determine chromium (Cr) in Huong river and Cau Hai lagoon sediment samples in Thua Thien Hue province. The method with two types of working electrodes (BiFE in situ và BiFE ex situ) and three kinds of acid mixtures used for wet-oxidation sample digestion prior to analysis were investigated for a certified reference material (fresh-water sediment material NCS DC87101 -GBW 07418). The SqW-AdSV using BiFE ex situ with the sample digestion in the mixture of HCl, HNO3 and HF gained good repeatability and trueness. The procedure was successfully applied to determination of Cr in the sediment samples collected from seven sites in Cau Hai lagoon (in February 2015) and eleven sites in Hương river (in February 2014). The obtained results shown that chromium content in the river sediment samples (0.01 - 4.5 ppm dry weight) lower than those in the lagoon sediment samples (5.6 - 20.9 ppm dry weight) and both of the contents were lower than the requirement of national technical regulation QCVN 43:2012/BTNMT set up for sediment quality.