Speciation of hexavalent chromium in atmospheric particulate samples by selective extraction and ion chromatographic determination

The predominant use of chromium in industry unfortunately causes environmental concern. In this respect, elaboration and improvement of the extraction process of hexavalent chromium (Cr(VI)) in atmospheric particulate matter followed by quantitative determination using an ion chromatographic method was performed. The detection of Cr(VI) is based on colorimetric absorbance measurement at 520 nm by variable UV/VIS detector. The elution process was performed by complex formation of Cr(VI) with pyridine-2-6-dicarboxylic acid (PDCA) followed by post-column derivatization reaction of the effluent with 1,5 diphenyl carbohydrazide (DPC). Improvement in selective extraction of Cr(VI) was carried out using carbonate/bicarbonate mixture in phosphate buffer/magnesium sulfate solution. Performance characteristics of the improved method, including limits of detection, precision and recovery of the spiked air sample were also investigated. Interference effects arise because of the presence of various reducing species, such as Cr(III) and Fe(II), but the extraction process developed their performance. (C) 2002 Published by Elsevier Science B.V. All rights reserved.