Determination of Nitrite with FI-Spectrophotometric Analysis

A new flow-injection catalytic kinetic spectrophotometric method was proposed to rapidly determinate trace amounts of nitrite.The proposed method is based on the accelerating effect of nitrite on the reaction between potassium chlorate and methylene blue in strongly acidic media and combines the flow injection.Under the selected conditions,the calibration graph is linear in the nitrite mass concentration ranges of 5 to 150 μg/L and 150 to 1 000 μg/L,and the detection limit is 1 μg/L.The relative standard deviation is respectively 3.1% for 10 μg/L nitrite(n,number of samples,is 11) and 4.6% for 100 μg/L nitrite(n=11).The proposed method has been applied to the determination of nitrite in natural water samples,the standard deviation is 1.1% to 3.4% and the recovery is 97.6% to 100.3%.