Simultaneous determination of chromium(III) and chromium(VI) in aqueous solutions by ion chromatography and chemiluminescence detection

Abstract

A method for the simultaneous determination of chromium(III) and chromium(VI) in a flow system based on chemiluminescence was developed. A Dionex cation-exchange guard column was used to separate chromium(III) from chromium(VI), and chromium(VI) was reduced by potassium sulfite, whereupon both species were detected by use of the luminol–hydrogen peroxide chemiluminescence system. Linear calibration for both species was established over the concentration range 1–1000 µg l^–1. The precision at the 20 µg l^–1 level was 3.5% for chromium(III) and 3.3% for chromium(VI), respectively. The detection limit was 0.5 µg l^–1 for both species. Data were in agreement with Zeeman-effect background corrected atomic absorption spectrometry measurements.