Enhancement of native fluorescence intensity of berberine by (2-hydroxypropyl)-β-cyclodextrin in capillary electrophoresis coupled by laser-induced fluorescence detection: Application to quality control of medicinal plants

A sensitive method for the determination of berberine, a plant alkaloid, was developed by capillary electrophoresis coupled with laser induced fluorescence detection. With the addition of (2-hydroxypropyl)-β-cyclodextrin (2-HP-β-CD) to the separation electrolyte, the low fluorescence signal intensity of berberine in aqueous medium was enhanced considerably by 162 fold. The optimal background electrolyte was selected as 20 mM acetic acid, 35 mM 2-HP-β-CD, and 20% methanol at pH 5. The limit of detection of the method for berberine was 15.7 ng/mL. The intra and interday repeatabilities of corrected peak areas as RDSs were 1.83% and 3.75%, respectively. The developed method was successfully applied for the determination of berberine contents in Chinese medicinal plants and herbal supplemental tablets.