Speciation of Cr(III) and Cr(VI) in potable waters by using activated neutral alumina as collector and ET–AAS for determination

Abstract.

The speciation of Cr(III) and Cr(VI) has been performed by using activated neutral alumina as adsorbent. Both species were quantitatively adsorbed on a small column filled with neutral alumina. The adsorbed Cr(III) was eluted with 4 mol L^–1 HNO₃ and Cr(VI) with 1.0 mol L^–1 ammonia solution. Recoveries of Cr(III) and Cr(VI) were 99% and 100%, respectively. Using ET–AAS for Cr determination the limit of detection in the sample was 0.01 µg L^–1. The combined procedure is fast and sensitive. It can be applied for routine analysis of water samples at sub-µg L^–1 levels with a relative standard deviation (RSD) of 2–10% (three determinations).