The fluorescence of 8-(3’,4’-diaminophenyl)-difluoroboradiaza-s-indacene is very weak, but when it reacts with nitrite, a strong fluorescent triazole forms in aqueous medium at 30 ℃, which offers the advantages of specificity and sensitivity for the determination of nitrite. Nitrate can be reduced to nitrite by zinc and cadmium chloride. Based on this, a new method is developed for sensitive determination of nitrite and nitrate in food products by spectrofluorimetry. The response is a linear function of concentration in the range of 0.06～6 μmol•L－1. The detection limit is 2 nmol•L－1 (S/N＝3). The proposed method has been used for the determination of trace level of nitrite and nitrate in food products with the recoveries of 98.16%～103.20%.

Key words: 8-(3’,4’-diaminophenyl)-difluoroboradiaza-s-indacence, spectrofluorimetry, nitrite, nitrate