Determination of ellagic acid by fluorescence quenching method with glutathione capped CdTe quantum dots as the probe

A sensitive and simple method for the determination of ellagic acid (EA) was developed based on the fluorescence quenching effect of EA for glutathione (GSH)-capped CdTe quantum dots (QDs). Under optimum conditions, a good linear relationship was obtained from 0.3118 to 55.0 μg mL−1 with a correlation coefficient of 0.9983, and the detection limit (3σ/K) was 0.0936 μg mL−1. The fluorescence quenching mechanism has been proposed on the basis of electron transfer supported by ultraviolet-visible (UV-vis) absorption, fluorescence (FL) spectroscopy and the measurement of fluorescence lifetime. The method has been applied to the determination of EA in synthetic samples and fresh urine samples of healthy humans with satisfactory results. The proposed method manifested several advantages such as high sensitivity, short analysis time, low cost and ease of operation.