Xevo g2 xs quadrupole time of flight q tof mass spectrometer

An Acquity UPLC BEH C₈ column (2.1 × 100 mm, 1.7 μm) was used for lipid separation using a mobile phase composed of 5 mM ammonium formate with acetonitrile/water (A, 6:4; v/v) and 5 mM ammonium formate with isopropanol/acetonitrile (B, 9:1; v/v). Linear elution gradient settings for separation were: 0–1.0 min, 100% A; 1.0–2.0 min, 100–70% A; 2.0–12.0 min, 70–30% A; 12.0–12.5 min, 30–5% A; 12.5–13.0 min, 5–0% A; 13.0–14.0 min, 0% A; 14.0–14.1 min, 0–100% A; and 14.1–16.0 min, 100% A. The column was maintained at 55°C. An ACQUITY UPLC connected to a XEVO-G2XS quadrupole time-of-flight (QTOF) mass spectrometer (Waters, Manchester, NH, USA) in ESI+ mode was used for untargeted lipidomics analyses with the following settings: desolvation gas at 800 L/h and 400°C; cone gas at 50 L/h; source temperature at 100°C; capillary and sampling voltages of 2,000 V and 40 V, respectively. Mass data were acquired in MS^E mode at a ramping collision energy of 10–60 V. Data accuracy was ensured using a LockSpray™ source, with the (M+H)+ ions of leucine-enkephalin being set at m/z 556.2771 for the lock mass in ESI+ mode. Sample profiling data were acquired from 50 - 1,200 Da. A UHPLC system (Waters Acquity) with a Xevo TQ-S mass spectrometer and an ESI ionization source was used for targeted lipidomics analyses conducted using multiple reaction monitoring (MRM) in positive ion modes.

DESI-MSI data were acquired applying Xevo G2-XS quadrupole time of flight (Q-TOF) mass spectrometer (Waters, Milford, MA, USA) coupled to a 2D-DESI source. After calibrating mass spectra and optimizing the signal intensity of DESI-QTOF following the previous method [39 (link)], DESI-MSI data was acquired from standard drugs applied on glass slides (0.3 μL/spot) to confirm the detection. Thereafter, DESI-MSI data were acquired from mice kidney and brain sections in positive ion mode at an m/z range of 150 to 550. All parameters used for the optimization of DESI-MSI and data acquisition are given in Table S3.

Data were acquired from WT and SAMP8 mice brain sections in positive ionization mode using Xevo G2-XS quadrupole time of flight (Q-TOF) mass spectrometer (Waters, Milford, MA, USA) coupled to a DESI source. Using a solution of sodium formate (500 µM) in 90% 2-propanol (10: 90; water: 2-propanol, v/v), mass spectra were calibrated prior to the measurement. As spray solvent, 98% methanol (98:2; methanol: water, v/v) was sprayed at 2 µL/min. Ions from the sagittal brain sections were obtained over m/z range of 500–1000 (Dalton) Da. Following parameters were used for the optimization of DESI to get best signal intensity on tissue prior to acquire data: capillary voltage, 4.0 kV; cone voltage, 40 eV; capillary temperature, 130 °C; nebulizing gas (nitrogen gas) pressure, 4.0 bar; spatial resolution, 100 μm; incidence angle of sprayer, 75 degree; inlet to sprayer distance, about 10 mm; sample to sprayer distance, about 1 mm; scan speed, 200 μm/sec and mass window of 0.02 Da. For better mass accuracy, lock mass correction was performed using m/z 798.5410; exact m/z of PC (34:1), the most abundant PC found in brain [48 (link)].