Ratio-fluorescence detection of propyl gallate based on MnOOH nanoflakes and β-cyclodextrin modified quantum dots

A ratiometric fluorescent probe was developed for the first time to quantitatively analyze propyl gallate (PG). The probe utilizes the fluorescence enhancement of Schiff base formed by PG and polyethyleneimine (PEI) catalyzed by MnOOH nanosheets, and the quenching effect of PG on quantum dots modified by β-cyclodextrin. Upon excitation at 350 nm, the fluorescence intensity of the dual-emission probe increased at 470 nm and decreased at 595 nm. The probe was successfully employed for the determination of PG in food samples in the concentration range of 0.1-35 μg/mL. The limit of detection (LOD) and the limit of quantitation (LOQ) were determined to be 0.023 μg/mL and 0.077 μg/mL, respectively. The recovery rate was found to range from 88.5 % to 103 % across three levels of spiked experiments. In conclusion, the present study provides a highly selective and sensitive analytical method for the detection of PG in real samples.