Determination of hexavalent chromium in South African cements and cement-related materials with electrothermal atomic absorption spectrometry

The selective extraction of Cr(VI) in a cement matrix, based on treatment with 0.1 M Na 2CO 3 solution and subsequent determination of chromium by electrothermal atomic absorption spectrometry has been proposed. The proposed method has been applied to South African cement clinkers, natural gypsum, limestone and certified reference materials. The limit of detection of chromium determination in cement samples was found to be 0.14 μg g −1. Between 30% and 80% of the total chromium in South African cement clinkers are Cr(VI) compounds and 8–26% of the total amount of Cr(VI) species is water soluble. The analytical performance of the proposed method has been verified by the analysis of BCS-CRM, a sulphate-resisting Portland cement, and the results obtained were in good agreement with the certified values.