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Spectrophotometric Determination of Hexavalent Chromium Content in Commercial Cement – an Assessment of the Optimal Conditions for the Analysis of Chromium (VI)


Krasimira A. Stancheva, Bogdan I. Bogdanov, Dimitar P. Georgiev, Yancho H. Hristov, Irena G. Markovska

Article (PDF)

Keywords

Hexavalent chromium in cement; spectrophotometric determination

Abstract

Throughout the world the content of hexavalent chromium in cement is under control. In Europe, the new restrictions on the amount of this substance prohibit the use of cement having concentration more than 2 ppm. However, hexavalent chromium contents in cements above 2 mg kg-1 are still found frequently. The study represents a contribution to the establishing of possible limitations of this compound. The analyses showed that 7 of 10 cements analyzed by us satisfy the requirements for limit value of 2 ppm for water-soluble chromium (VI) in cement available in our market. Chromium (VI) was analyzed using the reference diphenylcarbazide spectrophotometric method from TRGS 613. The results for the absorbance spectra showed that maximum absorbance peak of the hexavalent chromium complex was at 538.7 nm. It was recorded in the range 25-200μg Cr(VI) L-1) using Varian Cary 50 reader system. Parameters such extraction time in dependence of the rotary of the stirring and wavelength variation were optimized and the results obtained were satisfying. In the present work а cement sample from the Devnya manufacturer was tested and it was found that this cement satisfies the European standard requirements. Finally, this application describes a simple and rapid, costeffective analysis to measure low levels of hexavalent chromium.