Rapid Determination of Chromium (M)lli Natural Water and Industrial Effluents Using Kinetic Speetrophotometric Method

Abstract

A new simple arid rapid catalytic kinetic method for determination of trace amounts of chromium (110 is<br />described. The method is based on the catalytic effect of chromium (III) on the reduction of Methylene blue by<br />ascorbic acid in acidic media. The reaction monitored smectrophotomenically by measuring the decrease of<br />absorbance at 664 nm at 25 C. The fixed-time method was used for the first 300 s. Under the optimum<br />conditions, the amount of Cr(111) in the concentration range of 0.5 - 520.0 wg ml_dt (III) can be determined with<br />a limit of detection of 0.09 wg mL- of chromium (111). The relative standard deviations of six replicate<br />measurements are 2.8 and 2.1% for 50.0 and 500.0 wg rni.-1 of chromium (III), respectively. The effect of<br />certain foreign species upon the reaction rate was investigated for the assessment of the selectivity of the<br />method The proposed method was successfully applied to the determination of chromium (III) in real samples<br />with satisfactory results. The new developed method was found to have fairly goad seleethity, sensitivity,<br />rapidity, reproduceability and simplicity