RESUMEN
In this study, a method for the determination of pepsin using a 3-hydroxyflavone (3-HF)-bovine serum albumin (BSA) complex as a fluorescent probe was established. Under acidic conditions, 3-HF can react with BSA to emit strong green fluorescence, which involves an excited state intramolecular proton transfer and fluorescence resonance energy transfer. After pepsin is added, the fluorescence of the 3-HF-BSA system is quenched due to the hydrolysis of BSA. The degree of 3-HF-BSA fluorescence quenching has a good linear relationship with the concentration of pepsin in the range of 10-80 µg/mL. The correlation coefficient was R2 = 0.9932 and the detection limit was 2.41 µg/mL. This method has high selectivity and good stability and has been used to determine pepsin in real samples with satisfactory results.