1290 series

Lipid profiling was performed by a UHPLC system (1290 series, Agilent Technologies, USA) coupled with a quadruple time-of-flight mass spectrometer (Triple TOF 6600, AB SCIEX, USA). Phenomenex Kinetex C18 100 A column (1.7 μm, 2.1×100 mm) (Phenomenex, USA) was used for the lipid extracts separation. The column was maintained at 25°C. The linear gradient started from 60% to 0% A (10 mmol/L ammonium formate, ACN: H2O = 6:4) and 40% B (10 mmol/L ammonium formate, IPA: H₂O = 9:1). Gradient conditions were as follows: 0–12 min linear gradient from 40 to 100 % B, 12–13.5 min 100 % B. The flow rate was 300 μL/min. The injected sample volume was 1 μL. Data acquisition and processing were performed with the acquisition software Analyst TF (version 1.7.1, AB SCIEX, USA), which could acquire high resolution MS and tandem-MS data simultaneously by TOF MS full scan and information-dependent acquisition (IDA) in both ESI(+) and ESI(−) modes. The source parameters were set as follows: GAS1: 60 psi; GAS2: 60 psi; CUR: 30 psi; TEM: 600°C; -4500 V in negative mode; CE: 45± 25 eV.

LC-MS analysis was performed using a UHPLC system (1290 series, Agilent Technologies) coupled to a quadruple time-of-flight mass spectrometer (6550 series, Agilent Technologies). Merck SeQuant ZIC-pHILIC column (particle size, 5 μm; 100 mm (length) ×2.1 mm (i.d.)) was used. Mobile phases A = 25 mM ammonium acetate and 25 mM ammonium hydroxide in 100% water, and B = 100% acetonitrile, were used for both ESI positive and negative modes. And the linear gradient eluted from 80% B (0.0–2.0 min, 0.2 mL/min), 80% B to 20% B (2.0–17.0 min, 0.2 mL/min), 20% B to 80% B (17.0–17.1 min, 0.2 mL/min), 80% B (17.1–22.1 min, 0.4 mL/min), 80% B to 80% B (22.1–22.2 min, 0.2 mL/min). The sample injection volume was 2 μL.
ESI source parameters on QTOF 6550 were set as followings: sheath gas temperature, 300°C; dry gas temperature, 250°C; sheath gas flow, 12 L/min; dry gas flow, 16 L/min; capillary voltage, 2500 V or −2500 V in positive or negative modes, respectively; nozzle voltage, 0 V; and nebulizer pressure, 20 psi. The MS1 data acquisition frequency was set as 4 Hz, and the TOF scan range was set as m/z 60–1200 Da.

The determination was performed on an Agilent 1290 series liquid chromatography system and an Agilent 6470 triple-quadruple mass spectrometer (Palo Alto, CA, USA). The chromatographic analysis of omeprazole was performed on a Waters Xbridge C18 column (3.0 × 100 mm, i.d.; 3.5 μm) at room temperature. The mobile phase was water (containing 0.1% formic acid) and acetonitrile (25:75, v:v) at a flow rate of 0.3 mL/min. The mass scan mode was positive MRM mode. The precursor ion and product ion are m/z 345.8 → 197.7 for omeprazole and m/z 339.0 → 176.9 for esculin, respectively. The collision energy for omeprazole and IS was 20 and 35 eV, respectively. The MS/MS conditions were optimized as follows: fragmentor, 110 V; capillary voltage, 3.5 kV; nozzle voltage, 500 V; nebulizer gas pressure (N₂), 40 psig; drying gas flow (N₂), 10 L/min; gas temperature, 350 °C; sheath gas temperature, 400 °C; sheath gas flow, 11 L/min.