Simultaneous determination of chromium(III) and chromium (VI) with reversed-phase ion-pair high-performance liquid chromatography
Abstract
A reversed-phase ion-pair high-performance liquid chromatographic method for the simultaneous determination of CrIII and CrVI in aqueous solution was developed. Chromium(III) was chelated with ethylenedi-aminetetraacetic acid (EDTA) prior to the analysis. A C8 column was used to separate the CrIII–EDTA complex from the CrVI ions using an eluent containing acetonitrile and tetrabutylammonium ion. The separated species were monitored at 242 nm using an ultraviolet (UV) detector. The factors affecting complex formation, the chromate stability and prospective interferences were investigated. The proposed method provides a simple analytical procedure for Cr speciation. The detection limits were 0.4 ng for CrIII and 1.6 ng for CrVI with a 20 µl injection. The relative standard deviations for CrIII and CrVI were 0.24 and 1.78%, respectively.