A novel ion mobility separation-enabled and precursor ions list-included high-definition data-dependent acquisition (HDDDA) approach: Method development and its application to the comprehensive multicomponent characterization of Fangji Huangqi Decoction

To elucidate the chemical composition of a traditional Chinese medicine (TCM) formula necessitates the development of more potent analytical strategies, because of the complexity as a result of the superposition of multiple drugs. Fangji Huangqi Decoction (FHD) is a four-component TCM formula composed by complicated chemical constituents. By using the VionTM ion mobility quadrupole time-of-flight (IM-QTOF) mass spectrometer, we present a novel IM separation-enabled and precursor ions list (PIL)-included high-definition data-dependent acquisition (HDDDA) approach, and apply it to the multicomponent characterization of FHD by coupling to ultra-high performance liquid chromatography. Chromatographic separation was conducted on a CORTECS® UPLC® T3 column, while HDDDA was employed for MS2 data acquisition in both the negative and positive electrospray-ionization (ESI) modes. The PILs of FHD in two ESI modes were created based on the phytochemical knowledge of four component drugs and mass defect filtering, which ultimately could obtain 316 and 258 targeted masses, respectively, from the full-scan MS1 data. Interestingly, the additional inclusion of PILs in HDDDA could improve the coverage on the target components by 12% (ESI–) and 48% (ESI + ). Structural elucidation was performed by in-house database-driven automatic peak annotation using UNIFITM. We could identify or tentatively characterize 203 components from FHD, involving 25 alkaloids, 86 flavonoids, 48 triterpenoids (saponins), 16 lactones, and 28 others). It is the first report regarding the method development of HDDDA that targets the global TCM components characterization, and the findings obtained would benefit the quality control and the secondary development of FHD.

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2. Materials and methods

In total, 62 compounds (the chemical structures are given in Fig. 1 and the detainled information offered in Table S1, as Supplementary Materials) involving 16 flavonoids (numberred as 1–16), 15 alkaloids (17–31), 7 saponins (32–38), and 24 others (39–62), purchased from  Chengdu Desite Biotechnology Co., Ltd. (Chengdu, China), were used as the reference compounds in this work. 

Fig. 1. Chemical structures of the 62 reference compounds.

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