A Highly Sensitive and Selective Spectrofluorimetric Method for the Determination of Nitrite in Food Products

摘要

This paper describes a simple, sensitive, and selective spectrofluorimetric method to determine trace amount of nitrite in food products using 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate (DAF-FM DA) as a fluorescent probe. The reaction of DAF-FM DA with nitrite in acidic medium resulted in triazolofluorescein (DAF-FM T), a highly fluorescent reagent in neutral medium. The fluorescence enhancement was proportional to nitrite concentration in the range of 5.0 x 10(-8) to 1.5 x 10(-6) mol L-1 with a detection limit of 3.3 x 10(-8) mol L-1 (S/N = 3). The proposed method has been applied to the determination of nitrite in real food samples, with relative standard deviation (RSD) (n = 6) less than 5.1 % and recoveries in the range of 86.4 similar to 102.9 %.