4.3.3. Acquisition Conditions of LC-MS

The data acquisition instrument system mainly includes Ultra Performance Liquid Chromatography (UPLC) (Shim-pack UFLC SHIMADZU CBM30A, http://www.shimadzu.com.cn/) and Tandem mass spectrometry (MS/MS) (Applied Biosystems 4500 QTRAP, http://www.appliedbiosystems. com.cn/).

UPLC was run under following conditions: (1) Waters ACQUITY UPLC HSS T3 C18 1.8 μm, 2.1 mm × 100 mm; (2) The aqueous phase was ultra-pure water (0.04% acetic acid is added) and the organic phase was acetonitrile (adding 0.04% acetic acid); (3) Elution gradients: 95:5 v/v at 0 min, 5:95 v/v at 11.0 min, 12 min, 12.1 min and 15 min; (4) The flow rate was 0.4 mL/min, the column temperature was 40 ◦C, and the injection volume was 5 μL. MS/MS worked with these conditions: (1) Curtain gas (CUR) was set to 25 psi; (2) Electrospray ionization (ESI) was set to 550 ◦C; (3) the MS voltage was set to 5500V; (4) Dclusteringotential (DP) was optimized; (5) Collision energy (CE) was optimized; (6) Collision-activated dissociation (CAD) was set to high.
