Serum Metabolomics

2.6. Chromatography and mass spectrometry conditionsThe chromatographic column used was ACQUITY UPLC BEH C18 (2.1×100 mm, 1.8 μm). The injection volume was 5 μL, with a column temperature of 40°C and a flow rate of 0.3 mL/min. The mobile phases were acetonitrile (A) and 0.1% formic acid-water (B). The elution gradient was as follows: 0–0.5 min (A) 5%, 0.5–1.5 min (A) 5–15%, 1.5–4.5 min (A) 15–30%, 4.5–6 min (A) 30–60%, 6–9 min (A) 60–70%, 9–12 min (A) 70–100%, 12–13 min (A) 100%, 13–13.5 min (A) 100%–5%, 13.5–16 min (A) 5%.Electrospray ionization (ESI) was used in both positive and negative ion scanning modes. The spray voltage was 3.2 kV, sheath gas flow rate 40 arb, auxiliary gas flow rate 5 arb, and auxiliary gas heating temperature 350°C. The ion transfer tube temperature was 320°C, S-Lens RF Level 50 V, scanning range 100–1000 m/z, and collision energy 30 eV.