Determination of trace amounts of nitrite by catalytic-kinetic spectrophotometric method

Abstract

A kinetic spectrophotometric method for the determination of trace amounts of nitrite is proposed based on the catalytic effect of nitrite on the oxidation of xylenol orange by bromate in acidic media The reaction is followed spectrophotometrically by monitoring the decrease in absorbance of xylenol orange at 430 nm with a fixed time of 0.5-4.0 minutes from initiation of the reaction and at 30&deg;C. Nitrite can be determined in the range of 0.001-0.100 <em>m</em>ml with limit of detection of 0.0003 <em>m</em>g/ml. The relative standard deviation for ten replicate measurements of 0.020 and 0.100 <em>m</em>g /ml of nitrite is 2.6% and 2.0%, respectively. The effect of potential interfering ions has been studied and the method used to determine the amount of nitrite in water samples.