A simple fluorescence quenching method for berberine determination using water-soluble CdTe quantum dots as probes

A novel method for the determination of berberine has been developed based on quenching of the fluorescence of thioglycolic acid-capped CdTe quantum dots (TGA-CdTe QDs) by berberine in aqueous solutions. Under optimum conditions, the relative fluorescence intensity was linearly proportional to the concentration of berberine between 2.5 x 10(-8) and 8.0 x 10(-6) mol L-1 with a detection limit of 6.0 x 10(-9) mol L-1. The method has been applied to the determination of berberine in real samples, and satisfactory results were obtained. The mechanism of the proposed reaction was also discussed. (C) 2009 Elsevier B.V. All rights reserved.