Determination of Trace Levels of Nitrite in Beverages Samples Through Micellar Improved Catalytic Kinetic Spectrophotometry

Abstract

In this study, a simple and sensitive catalytic kinetic spectrophotometry method for determination of nitrite has been described. The method is based on the oxidation of chlorpromazine by nitrite in presence of mixed surfactants in acidic medium, which results in the decrease in absorbance at 520 nm. Various chemical (such as the effect of acidity, reagents concentrations) and instrumental parameters (time, sample volume and temperature) were optimized. The interfering effects of various chemical species were studied. At the optimum conditions, linear calibration graph was linear in the nitrite concentration ranges of 2.5-125 µg L –1 . The detection limit is 0.71 µg L –1 for nitrite. The relative standard deviation for determination of 25 and 75 µg L –1 were 3.40 and 2.35%, for ten replicate measurements, respectively. The micellar improved catalytic kinetic spectrophotometry showed good analytical performance including good sensitivity, reproducibility, stability and selectivity to nitrite. The method has been applied to determine nitrite in beverages samples with a satisfactory recovery in the range of 97.3–103.8%, showing its promising application for food safety monitoring.