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Simple spectrophotometric determination of chromium in industrial effluents and water samples

Tom Cherian, B.Narayana

A simple, rapid and sensitive spectrophotometric method has been developed for the determination of chromium in industrial effluents and natural water samples. The method is based on the reaction of chromium(VI) with potassium iodide in acid medium to liberate iodine. This liberated iodine bleaches the violet color of the thionin. The decrease in absorbance at 600nmis directly proportional to the chromium(VI) concentration and obeys BeerÂ’s lawin the range 2-14 ìgmL-1 for chromium(VI).Themolar absorptivity, SandellÂ’s sensitivity, detection limit and quantitation limit of the method were found to be 0.967ï‚´104 Lmol-1cm-1, 1.08ï‚´10-2ìgcm-2, 0.034 ìgmL-1and 0.105 ìgmL-1 respectively. The optimumreaction conditions and other analytical conditions were evaluated. The effect of interfering ion on the determination is described. The chromium(III) can be determined after oxidation to chromium(VI). The developed method has been successfully applied to the analysis of the chromiumin industrial effluents and naturalwater samples.