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 ultratrace amounts of nitrite is described. It is based on the catalytic action of this anion on the oxidation of Brilliant Cresyl Blue by bromate, which yields a colorless product in acidic media. The reaction is followed spectrophotometrically by measuring the change in absorbance at 595 nm and 30-degrees-C. Nitrite in the range of 0.5-1000 ng/ml can be determined in the presence of large amounts of nitrate and ammonium ions. 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 determination of nitrite in natural waters, sausage, and salt. (C) 1994 Academic Press, Inc.