Kinetic spectrophotometric determination of trace nitrite in water samples with indigo carmine and potassium bromate redox system

A sensitive and selective kinetic spectrophotometric method for the determination of trace nitrite at25t was developed, based on its catalytic effect on the oxidation of indigo carmine with potassium bromate in1. 0 mol/L phosphoric acid medium. The linear calibration range and detection limit is 0. 2 ~ 1. 6 ug/ 10 mLand 0. 02 ug/mL respectively. The apparent activation energy of the quasi zero order catalytic reaction is39. 7 kJ/mol. The method is simple and rapid. Most of the common ions did not interfere to the determination of nitrite. The method is applied to the determination of nitrite in water samples with satisfactory results.