Simultaneous Determination of Amino Acids, Nucleosides, and Nucleobases in <i>Schisandra chinensis</i> Fructus from Different Regions Based on Liquid Chromatography Coupled with Q-trap MS/MS

Background Schisandra chinensis is a traditional Chinese medicine and is widely consumed as a health food due to its immune-enhancing properties. However, limited research has been done on its nutrient composition. Objectives In this study, liquid chromatography-tandem triple quadrupole mass spectrometry (LC-QTRAP-MS/MS) was developed for quantitative analysis of nucleosides, nucleobases (NNs), and amino acids (AAs) in 16 batches of S. chinensis samples collected from Liaoning, Jilin, and Heilongjiang provinces. Materials and Methods A Waters X-Bridge Amide column (2.1 × 100 mm, 3.5 µm) was used for analysis. The mobile phase consisted of A (water with 0.2% formic acid) and B (acetonitrile with 0.2% formic acid) with a flow rate of 0.6 mL/min. The column temperature was maintained at 30°C. The mass spectrometry was equipped with an electrospray ionization source and operated in positive ion multiple reaction monitoring (MRM) modes. Results The method demonstrated acceptable linearity within the tested concentration range. The average recovery of the 30 components ranged from 96.55% to 103.85%, with relative standard deviations (RSD) ranging from 1.02% to 2.88%. The quantitative data indicated that differences in the contents of NNs and AAs in S. chinensis from different regions were evident. The analysis of clustering heat maps revealed that the 16 batches of S. chinensis samples could be grouped into five categories. Stacked bar chart analysis showed that the levels of arginine and uridine were higher in most regions. Correlation analysis indicated strong correlations among the 14 AAs, with 42 groups showing significant relationships. Additionally, seven robust correlations were observed among the 16 NNs. Conclusion This established method provides essential data for the quality assessment and utilization of S. chinensis resources.