Determination of berberine in Rhizoma coptidis using a β-cyclodextrin-sensitized fluorescence method

In this work, a method for the determination of berberine in Rhizoma coptidis using β-cyclodextrin-sensitized fluorescence technology is established. Berberine is the main extract of Rhizoma coptidis, a medicinal material, which causes an envelope reaction with β-cyclodextrin to generate fluorescence sensitization. In the environment of its own aqueous extract, with 0.0065 mol L^-1 of β-cyclodextrin, a fluorescence excitation wavelength (λ _ex) of 345 nm and an emission wavelength (λ _em) of 540 nm were selected to avoid interference from other distractors. The fluorescent sensor for the detection of berberine exhibits a low limit of detection (3.59 × 10^-9 mol L^-1) and a wide linear range from 2.7 × 10^-7 mol L^-1 to 2.7 × 10^-6 mol L^-1. Our sensor can be also used to detect berberine in real medicinal materials. The content of berberine in Rhizoma coptidis medicinal material was found to be 7.60% using this method with an average recovery rate of 99.5%. The result obtained by thin-layer chromatography with fluorescence detection was 7.61%, which is consistent with the result from the β-cyclodextrin sensitized fluorescence method. This method is simple and environmentally friendly with high sensitivity and good selectivity and gives reliable results, which is promising for practical application.