Photometric Determination of Berberine Hydrochloride in Drugs Based on Its Reaction with Nanogold

Nanogold was prepared by reduction of chloroauric acid with glucose,and a reddish colored suspended solution of nanogold having its concentration of 2.4×10-4mol·L-1 was obtained finally.It was shown that the nanogold particles were homogeneously dispersed in the suspension and that an absorption peak at the wavelength of 525 nm was observed in the absorption spectrum.Due to electrostatic combination between nanogold particles and berberine hydrochloride molecules,the absorbance of nanogold suspension was decreased,and magnitude of decrease in absorbance (ΔA) was found to keep linear relationship with concentration of berberine hydrochloride in the range from 2.0×10-7 to 3.0×10-6mol·L-1,with its detection limit (3S/N) of 1.7×10-8mol·L-1.The proposed method was used in the analysis of berberine hydrochloride tablets,giving analytical results in consistency with the results found by the method given in pharmacopoeia.