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

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 degrees C. Nitrite can be determined in the range of 0.001-0.100 mu g/ml with limit of detection of 0.0003 mu g/ml. The relative standard deviation for ten replicate measurements of 0.020 and 0.100 mu 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.