[Screen astragalosides from Huangqi injections by LC-TOF-MS-based mass defect filtering approach]

The samples of Huangqi injection (HI) were analyzed by liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (LC-TOF-MS), and both positive and negative ion modes were employed to obtain the LC-TOF-MS analysis information of chemical compounds in HI. Then the mass defect filtering (MDF) approach, which was developed based on the previously published articles, was utilized to rapidly screen the astragalosides from the obtained LC-TOF-MS data. Each screened astragaloside was confirmed by the presence of no less than 2 quasi-molecular ions. All the screened astragalosides were then tentatively assigned according to the parent ion and daughter ion information. Finally, a total of 62 astragalosides were screened and characterized from the HI samples, including 15 new detected ones. The identification results indicated that acetylation, hydrogenation, dehydrogenation, methoxylation and hydration might be the major conversion reactions involved in the formation of the astragalosides. The LC-TOF-MS-based MDF approach was proved to be a feasible and efficient tool to screen the chemical constituents in complex matrices such as herbal medicines.