Rapid classification and identification of complex chemical compositions in traditional Chinese medicine based on UPLC-Q-TOF/MS coupled with data processing techniques using the KuDieZi injection as an example

The KuDieZi (KDZ) injection is prepared by extracting and processing Ixeris sonchifolia [Ixeris sonchifolia Hance] belonging to Lactuca genus of the Asteraceae family. The KDZ injection is a single-herb preparation in which the components are analysed by liquid chromatography-mass spectrometry. However, the chemical compositions of this preparation are complex and diverse. Hence, data processing is complicated and time consuming; furthermore, data processing cannot provide a systematic, accurate and repeatable method to rapidly classify and identify chemical constituents of the injection. In our study, the main components, particularly flavonoids, organic acids, amino acids and nucleosides in the KDZ injection, were rapidly classified and identified by data processing technology based on UPLC-Q-TOF/MS. After we reviewed lots of studies and collected information on the fragments, then compared them with the mass spectrometric analyses of the standards, the rules of diagnostic fragments (DFs) and neutral losses (NLs) of the four substances were found and summarised. A rapid classification and identification method of the chemical composition in the KDZ injection was then constructed using the DF filter (DFF) and the NL filter (NLF). This method was applied to analyse the KDZ injection. A total of 31 chemical components, which included 8 flavonoids, 13 organic acids, 6 amino acids and 4 nucleosides, were obtained. DFF and NLF were used to rapidly classify and identify chemical substances in the KDZ fingerprint. With this method, we effectively solved the technical difficulties in fingerprint resolution caused by complex components and low levels in traditional Chinese medicine (TCM). In addition, this study provided a novel approach for further studies on TCM.