Abstract:

Phosphatidylcholine （PC） and lysophosphatidylcholine （LPC） homologues are closely associated with coronary atherosclerosis. Accurate determination of their contents can provide an important basis for the clinical diagnosis and prognosis of coronary artery disease （CAD）. In this study， an analytical method based on liquid chromatography-tandem mass spectrometry was established， which enabled the simultaneous and accurate determination of 30 PC and LPC homologues using only 10 μL of human serum. Methanol-acetonitrile-methyl tert-butyl methyl ether-water was used as the extraction system， and an XBridge C18 column was selected as the stationary phase. The mobile phase consisted of an acetonitrile-water mixture （1∶1， volume ratio） and isopropanol， both containing 7.5 mmol/L ammonium formate and 0.15% （volume ratio） formic acid， and gradient elution was adopted for separation. Detection was performed using an electrospray ionization source in the positive ion mode with multiple reaction monitoring. Method validation results showed that the method exhibited a good linear relationship， with an average linear correlation coefficient of ≥0.999 7 over a linear range of 0.125-100 μg/mL. The limits of detection and limits of quantification were 0.01-1.94 μg/mL and 0.03-6.48 μg/mL， respectively. The recoveries ranged from 85.4% to 114.3%， while the intra-day precision and inter-day precision were no more than 4.6% and 12.6%， respectively. Serum samples from 110 clinical volunteers who underwent coronary angiography were determined using this method. The average population concentration of PC homologues was 526.80 μg/mL， and that of LPC homologues was 73.67 μg/mL. Spearman correlation analysis revealed that PC and LPC homologues were closely correlated with the severity of CAD， as well as with related clinical biochemical and lipid metabolism indicators， suggesting that they could serve as potential CAD-related metabolites in clinical practice. Designed to meet clinical analysis needs， this method features small serum sample volume， simple operation， and excellent response. It can efficiently determine 30 PC and LPC homologues in human serum， providing an important reference for exploring the association between these two lipid classes and CAD， as well as the translational application of related biomarkers.

Key words: phosphatidylcholine, lysophosphatidylcholine, atherosclerosis, coronary artery disease, liquid chromatography-tandem mass spectrometry （LC-MS/MS）, lipidomics