[Determination of trace chromium(VI) by catalytic spectrofluorimetry using pyronine Y-H2O2-Cr(VI) system]

A simple and highly sensitive new kinetic catalytic fluorimetric method was proposed for the determination of trace chromium (VI), based on the catalytic effect of trace amounts of chromium (VI) on the oxidation of Pyronine Y by hydrogen peroxide in acetic acid-sodium acetate buffer medium leading to a decrease in the fluorescence intensity. The optimum conditions and kinetic properties of the catalytic reaction were also studied. The apparent activation energy and the apparent rate constant are 159. 92 k * x mol(-1) and 5. 7X10-2 s-1 respectively. The linear range of the calibration curve is 0. 02-0. 24 microg x mL(-1) and the detection limit is 0. 012 microg x mL(-1). The present method was applied to the determination of chromium(VI) in river water, and industrial and electroplating waste water with good results.