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

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.