Rapid identification of flavonoid compounds in Pericarpium Citri Reticulatae by online extraction-high performance liquid chromatography-diode array detection- quadrupole time-of-flight mass spectrometry

A simple method was developed for the rapid extraction, separation and identification by online extraction ( OLE) coupled with high performance liquid chromatography-diode array detection-quadrupole time-of-flight mass spectrometry (HPLC-DAD-QTOF-MS). For OLE strategy, a guard column filled with Pericarpium Citri Reticulatae powder (2.0 mg) was connected to manual injection valve by replacing the sample loop. Components were directly extracted and transferred to HPLC-DAD-QTOF-MS system by mobile phases without any extra operation. In comparison with offline heat-reflux extraction, OLE strategy presented higher extraction efficiency. A total of twenty-four flavonoid compounds were detected from Pericarpium Citri Reticulatae according to their retention times, UV spectra, accurate molecular masses, and fragment ions in MS/MS spectra. Neoeriocitrin, limocitrin-3-O-(3-hydroxy-3-methylglutarate)-glucoside and its isomer were discovered for the first time. It is concluded that the developed method offers new perspectives for the rapid separation and identification of natural products.