Catalytic spectrophotometric determination of trace chromium (VI) using cetyltrimethylammonium bromide as sensitizer

A new catalytic spectrophotometric method for the determination of trace Cr(VI) has been developed. The method is based on the catalytic effect of Cr(VI) on the discoloring reaction of alizarin red oxidized with hydrogen peroxide. The enchancing of discoloring reaction is remarkable in the presence of cetyltrimethylammonium bromide (CTMAB). Because of the addition of CTMAB, the sensitivity increases 4.8 times. The linear range of determination is 0.010 similar to 0.090 mg/L, the detection limit is 8.9 x 10(-4) mg/L, and the relative standard deviation is 1.9%(n = 9),The method has been used to the determiantion of Cr(VI) in waste water.