Fluorescence Measurement of Nitrite Using Coumarin Derivative Based on Inner Filter Effect

High-performance measurement of nitrite (NO2−) is of significant importance in both food safety and health problems. In the present study, we established a fluorescent sensor for selective detection of nitrite using 3-acetoacetyl-7-diethylaminocoumarin (ADC) and 3-aminophenol (3-Aph) based on a simplified Griess reaction and inner filter effect (IFE). Under the strong acid conditions, the rapid reaction between 3-Aph and nitrite formed an azoic compound (AZO) with the color change from colorless to brown. The complementary spectral overlap between the absorption of AZO and the excitation of ADC induced the occurrence of IFE, leading to the fluorescence quenching of ADC. Under the optimum conditions selected, the proposed sensor exhibited a good linear range from 0.1 μM to 50 μM (R2 =0.9938) with the detection limit of 24.6 nM. Besides, successful detecting nitrite in real pickle and bacon samples showed a maximum 5% relative error with the acceptable recoveries, demonstrating that the promising strategy could be provided for nitrite analysis in real applications.