KINETIC-SPECTROPHOTOMETRIC DETERMINATION OF NITRITE BY ITS CATALYTIC EFFECT ON THE OXIDATION OF BRILLIANT CRESYL BLUE BY BROMATE

A kinetic-spectrophotometric method for the determination of ultratrac e amounts of nitrite is described. It is based on the catalytic action of this anion on the oxidation of Brilliant Cresyl Blue by bromate, w hich yields a colorless product in acidic media. The reaction is follo wed spectrophotometrically by measuring the change in absorbance at 59 5 nm and 30-degrees-C. Nitrite in the range of 0.5-1000 ng/ml can be d etermined in the presence of large amounts of nitrate and ammonium ion s. The limit of detection is 0.10 ng/ml. The proposed method is mostly free of interferences. The fixed-time method was used for the determi nation of nitrite in natural waters, sausage, and salt. (C) 1994 Acade mic Press, Inc.