%0 Journal Article
%T Spectrophotometric determination of nitrite by its catalytic effect on the oxidation of congo red with bromate
%A Zenovia Moldovan
%J Bulletin of the Chemical Society of Ethiopia
%D 2012
%I Chemical Society of Ethiopia
%X A novel simple, sensitive and rapid kinetic-spectrophotometric method for the determination of trace amounts of nitrite is proposed. The method is based on its catalytic effect on the oxidation of congo red (CR) by potassium bromate in acidic solution. The oxidation reaction is monitored spectrophotometrically by measuring the decrease in the absorbance of CR at a suitable ¦Ëmax= 570 nm for the first 10¨C40 s from the start of the reaction. Under the optimum experimental conditions (sulfuric acid, 0.3 M; CR, 0.75x10-4 M; potassium bromate, 5x10-4 M and 25 oC), nitrite can be determined in the range of 0.015¨C0.75 ¦Ìg mL 1 with the detection limit of 0.006 ¦Ìg mL 1. The relative standard deviation of five replicate determination of 0.25 ¦Ìg mL 1 nitrite was 2.5%. The proposed method was applied satisfactorily to the determination of nitrite in spiked drinking water samples.   KEY WORDS: Nitrite, Catalytic effect, Congo red, Spectrophotometry, Drinking water   Bull. Chem. Soc. Ethiop. 2012, 26(2), 159-169. DOI: http://dx.doi.org/10.4314/bcse.v26i2.1
%U http://www.ajol.info/index.php/bcse/article/view/77869