rapid determination of chromium (m)lli natural water and industrial effluents using kinetic speetrophotometric method

a new simple arid rapid catalytic kinetic method for determination of trace amounts of chromium (110 isdescribed. the method is based on the catalytic effect of chromium (iii) on the reduction of methylene blue byascorbic acid in acidic media. the reaction monitored smectrophotomenically by measuring the decrease ofabsorbance at 664 nm at 25 c. the fixed-time method was used for the first 300 s. under the optimumconditions, the amount of cr(111) in the concentration range of 0.5 - 520.0 wg ml_dt (iii) can be determined witha limit of detection of 0.09 wg ml- of chromium (111). the relative standard deviations of six replicatemeasurements are 2.8 and 2.1% for 50.0 and 500.0 wg rni.-1 of chromium (iii), respectively. the effect ofcertain foreign species upon the reaction rate was investigated for the assessment of the selectivity of themethod the proposed method was successfully applied to the determination of chromium (iii) in real sampleswith satisfactory results. the new developed method was found to have fairly goad seleethity, sensitivity,rapidity, reproduceability and simplicity