Altis mass spectrometer

5 µL of serum extract was injected into a Vanquish UHPLC system (Thermo Fisher, San Jose, CA, United States). The mobile phase was methanol with 0.5% formic acid and 10 mM Ammonium Formate. The separation was carried out using isocratic elution with at a flow rate of 0.10 ml/min. The eluted metabolites were detected by an Altis mass spectrometer (Thermo Fisher) operated in SRM setup using APCI positive mode. The conditions of ionization source were set at 6 µA for ion discharge current, 20 for sheath gas, 5 for aux gas, 300°C for ion transfer tube temperature, 300°C for vaporizer temperature. The MS spectra were acquired using an cycle time of 1 and Q1 resolution (FWHM) of 0.7, Q3 resolution (FWHM) of 0.7, CID gas of 1.5, chromatographic peak width of 12. The column oven was maintained at 30°C throughout the analysis.
Multiple reaction monitoring (MRM) is the most common targeted method for quantitation of analytes by LC/MS/MS. In MRM, ions are selected to make it through the first quadrupole and into the collision cell. In this study, the transition from precursor/parent ion to product/daughter ions is referred to as an ion transition (Supplementary Table S1).

2 µl of serum extract was injected into a Vanquish UHPLC system (Thermo Fisher, San Jose, CA, United States). The mobile phase A was water with 0.5% formic acid and10 mM Ammonium Formate, mobile phase B was methanol with 0.5% formic acid and10 mM Ammonium Formate. The separation was carried out using isocratic elution with 50% B at a flow rate of 0.10 ml/min. The eluted metabolites were detected by an Altis mass spectrometer (Thermo Fisher) operated in SRM setup using electrospray positive mode. The conditions of ionization source were set at 3.5 kV for spray voltage, 20 for sheath gas, 5 for aux gas, 300°C for ion transfer tube temperature, 200°C for vaporizer temperature. The MS spectra were acquired using an cycle time of 0.8 and Q1 resolution (FWHM) of 0.7, Q3 resolution (FWHM) of 0.7, CID gas of 1.5, chromatographic peak width of 12. The column oven was maintained at 30°C throughout the analysis.