An intelligentized strategy for endogenous small molecules characterization and quality evaluation of earthworm from two geographic origins by ultra-high performance HILIC/QTOF MSE and Progenesis QI

Animal-derived medicines have been a vital component for traditional Chinese medicine. However, their quality control remains challenging due to the large polarity of the contained endogenous small molecules (ESMs) that are difficult to separate by reversed-phase HPLC. Herein, an intelligentized strategy by ultra-high performance hydrophilic interaction chromatography/quadrupole time-of-flight mass spectrometry (HILIC/QTOF-MSE) is presented, and used for the ESMs characterization and differentiation of two geographic origins of earthworm (Guang Di-long, GD; Hu Di-long, HD) as a case study. Chromatographic separation was performed on a BEH Amide column (2.1 x 100 mm, 1.7 mu m). The MSE data in both negative and positive ion modes were acquired to record the high-accuracy MS and MS/MS data of all precursor ions. Automatic data processing was enabled by use of Progenesis QI software. As a consequence, 926 metabolites among 4705 features and 761 among 3418 features were characterized in the negative and positive modes, respectively, by searching the human metabolome database (HMDB). To reduce the false positive identifications, structural confirmation was conducted by comparison with the reference standards (t(R) and MS, MS/MS data) or matching with theoretical data or commercial library. Principal component analysis (PCA) of the GD and HD samples showed distinct classifications. Further orthogonal partial least squares discriminant analysis (OPLS-DA) and variable importance in projection (VIP) plot revealed the potential discriminatory markers between GD and HD. The present study provides a powerful and practical strategy that facilitates the primary metabolites characterization and quality evaluation of animal-derived medicines more efficiently.