UPLC/Q-TOFMS/MS as a powerful technique for rapid identification of polymethoxylated flavones in Fructus aurantii

Polymethoxylated flavones (PMFs), as potential cancer chemopreventive agents, are widely distributed in Citrus genus. In this study, a selected ion monitoring–tandem mass (SIM–MS/MS) method for the rapid identification of PMFs in Fructus aurantii (F. aurantii) with ultra-performance liquid chromatography (UPLC) coupled to quadrupole, hybrid orthogonal acceleration time-of-flight tandem mass spectrometer (Q-TOFMS/MS) was proposed. The MS data for candidates, containing accurate mass and isotopic patterns for both precursors and their fragment ions, were acquired selectively. Based on the MS data, the mass spectrometric fingerprint (MSFP) for candidates, consisting of chemical formula and dissociation pattern, was determined. Comparing the MSFPs of the observed compounds with the diagnostic MSFP of the species, 44 PMFs were tentatively identified. The method was validated by tangeretin and sinensetin, two representative compounds of PMFs, and was considered to be suitable for the rapid screening of PMFs in crude and partially purified samples.