Ultra-trace analysis of nitrite in food samples by flow injection with spectrophotometric detection

摘要

A flow injection system with spectrophotometric detection is proposed for the determination of low levels of nitrite based on its catalytic effect on the oxidation of gallocyanine by bromate in acidic media. Various analytical parameters such as acidity, reagent concentration, flow rate, sample size, time, temperature, and interfering species were studied. The calibration graph was linear for 0.020-0.500 #mu#g/mL of nitrite. The method is successfully applied to food samples. Up to 30 +- 5 samples can be analyzed per hour.