Determination of Cr (Iii) by Means of Atom Absorption Spectrometry

Abstract

The atomic absorption (AA) method is proposed for determination of trivalent chromium [Cr(III)] concentration in the samples containing the mixture of Cr (III) and Cr (VI). It was found that addition of chloric acid (HClO4) to Cr (III) solution substantially increases AA spectrometric signal. However, with the addition of HClO4 to Cr (VI) solution the signal remains unchanged. The addition of chloric acid to the mixture of chromium ions causes the increase of the signal of absorption that is related to the presence of Cr (III) ions. This fact allows quick and selective determination of Cr (III) concentration in the samples without prior separation of chromium compounds with different valences. The proposed method can be used for both atomic absorption spectrometry and atomic fluorescence spectrometry. Possibility of experimental application of the method is shown on the example of examination of interaction between Cr (VI) ions and chromium bacteria Arthrobacter oxydans.