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Simultaneous determination of water-soluble trivalent and hexavalent chromium by anion exchange high-pressure liquid chromatography.

Simultaneous determination of water-soluble trivalent (Cr (III)) and hexavalent chromium (Cr (VI)) was examined using anion exchange HPLC with a UV monitor and atomic absorption spectrophotometer (AAS). The eluting solution used was 0.03 M Na2CO3 (pH 11), and the flow rate was 2 ml/min. Cr (III) was changed into EDTA chelate before being submitted to chromatography. Sharp elution peaks of the Cr (III) chelate and Cr (VI) anions were obtained by both UV and AAS analyses. Retention time of the Cr (III) species was 2.2 min and that of the Cr (VI) was 5.5 min. The UV and AAS calibration curves for both chromium species showed good linearities. Detection limits of Cr (III) were 2 and 5 ng by UV and AAS analyses, respectively, and those of Cr (VI) were 0.2 and 5 ng. The recoveries of chromium ranged from 95% to 105%. Application of this method was able to determine the Cr (III) and Cr (VI) contents in the water extracts from chromium fume particles generated experimentally by a plasma flame method.