Analysis instrument: ultra-high performance liquid chromatography-triple quadrupole mass spectrometer;
Analysis conditions: an ACQUITY BEH HILIC column (100 mm × 2.1 mm, 1.7 μm); mobile phase A is 0.1% formic acid aqueous solution containing 20 mmol/L ammonium acetate, and mobile phase B is acetonitrile solution containing 0.1% formic acid; the monitoring mode is selected response monitoring in positive electrospray ionization mode;
Serum sample: 10 μL;
Serum diluent: 90 μL phosphate buffered saline;
Protein precipitant: 300 μL acetonitrile methanol solution (3:1, v:v) containing isotope internal standards composed of 10 μg/mL Cell Free Amino Acid Mix (20 AA) (U-D), 500 ng/mL O-acetyl-L-carnitine (N-methyl-D3), and 25 ng/mL lysophosphatidylcholine (20:0) (Eicosanoyl-12,12,13,13-D4).