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.