Comparison of the Analytical Performance of Two Columns Used for Determination of Chromium(vi) in Water

In the different compartments of the environmental chromium occurs mainly in the oxidation states (III) and (VI). Although Cr(III) is an essential trace element for humans, Cr(VI) is highly cancerogenic and mutagenic. It is, therefore, necessary for risk assessment not only to determine total chromium, but also to determine chromium species, especially Cr(VI). Hexavalent chromium can be determined as chromate (CrO4) by ion chromatography. In recent years ion chromatography has became a powerful technique for determination of ions, including inorganic and organic anions and cations. In the work discussed in this paper an ion-chromatographic method using ion-exchange columns and direct UV detection for determination of Cr(VI) in water samples has been validated. The analytical performance of Dionex IonPac AS7 and CS5A columns has been compared and method linearity and sensitivity, limit of determination, and limit of quantification calculated from peak area and peak height are given.