[Determination of trace nitrite by KBrO3-NO2(-)-zincon catalytic system]

A new catalytic kinetic spectrophotometric method for the determination of trace nitrite based on the oxidation reaction between KBrO3 and Zincon in H3PO4 medium has been developed. The optimum conditions for the rate of the reaction were studied, and the rate equation of the reaction was found to be -dcZincon/dt = k'cZincon.cBrO3-.CNO2-. The apparent activation energy and the apparent rate constant were 33.13 kJ.mol-1 and 1.32 x 10(-3).s-1, respectively, the detection limit was 6.0 x 10(-10) g.mL-1, and the range of determination was 0.60-30.00 micrograms.L-1. The method has been used to determine trace nitrite in water with satisfactory result.