Chemical Derivatization-Based Liquid Chromatography-Mass Spectrometry Method for Fatty Acid Profiling in Biological Samples

Fatty acids (FAs) are important metabolites for various biochemical functions in living organisms, including energy storage, cell structure, and cell signaling. Changes in FAs composition were significantly related to abnormal metabolic levels and body status. In this study, the derivatization-based liquid chromatography-quadrupole-orbitrap mass spectrometry method was established for FA analysis under parallel reaction monitoring mode. The 4-amino-1-benzylpiperidine (4A1BP) was used as a derivatization reagent to amide with FAs. The results showed that protonated molecules of FA+4A1BP–H₂O were observed, and characteristic fragment ions at m/z 174.1280 and 91.0548 were detected in the tandem mass spectrum. The derivatization method was optimized in terms of sample preparation, chromatographic separation, and mass spectrometric conditions. The linearity, stability, and repeatability of the method were also investigated with good results. Finally, we applied the established method to analyze the serum and liver tissue samples, successfully evaluating the efficacy of Qizha Shuangye granules in the treatment of hyperlipidemia rats. The established method has broad utility and great potential in the detection of FAs, which can provide technical support for disease mechanism research, biomarker discovery, as well as food quality assurance, and nutritional value evaluation.