Chemical fingerprint and simultaneous determination of flavonoids in Flos Sophorae Immaturus by HPLC-DAD and HPLC-DAD-ESI-MS/MS combined with chemometrics analysis

A simple and efficient HPLC method is developed for the fingerprint analysis of Flos Sophorae Immaturus and for the simultaneous determination of three flavonoids in Flos Sophorae Immaturus, namely rutin, narcissin and quercetin. The separation of analytes is conducted on a Dikma Diamonsil C-18 column ( 250 mm x 4.6 mm, 5 mm) at 35 degrees C; the wavelength of UV detector was set at 254 nm; the mobile phases were composed of acetonitrile and aqueous acetic acid ( 0.5%, v/ v). A gradient elution was carried out at a flow rate of 1.0 mL min(-1). A common chromatographic fingerprint consisting of 9 characteristic peaks is established among 14 batches of Flos Sophorae Immaturus samples, which were collected from different source areas of China. The constituents in Flos Sophorae Immaturus were further identified by HPLC-DAD-ESI-MS/MS and most of them were flavonoids. Multiple chemometrics analysis, including similarity analysis ( SA), hierarchical cluster analysis (HCA) and principal component analysis (PCA) were performed to classify samples. In quantitative analysis, all of the calibration curves showed good linear regression (R-2 >= 0.9991) within the tested ranges, and the mean recoveries ranged from 100.28% to 101.08%. Three flavonoid compounds in Flos Sophorae Immaturus were simultaneously quantified by the established method. The results demonstrate that the developed method is accurate and effective, and could be readily utilized for the comprehensive quality control of Flos Sophorae Immaturus.