Lc ms ms unit

For LC-MS/MS sample preparation, 100 µL plasma was mixed with 20 µL 50% methanol and 200 µL 4% phosphoric acid. Whole sample mixtures were added to an Oasis HLB 1 cc/10 mg extraction cartridge (Waters, MA, USA) equilibrated with 1 mL methanol and 1 mL distilled water. The column was washed with 1 mL 5% methanol and eluted with 1 mL methanol. The eluate was dried under nitrogen flow and dissolved in 100 µL solvent A/B (30%:70%, v/v) for LC-MS/MS. 10 µL samples were analyzed by a Waters LC-MS/MS unit. ACQUITY UPLC BEH HILIC, 1.7 µm, 2.1 mm I.D. × 100 mm (Milford, MA, USA), was used at a flow rate of 0.3 mL/min by linear gradient elution (solvent A: solvent B = 30%:70%, v/v; solvent A: 0.1% TFA, solvent B: acetonitrile) using electro-spray ionization for Xevo TQ MS (Waters).

For sample preparation, 100 μL plasma was mixed with 20 μL 50% methanol and 200 μL 4% phosphoric acid. Whole sample mixture was added to the Oasis HLB 1 cc/10 mg extraction cartridge (Waters) equilibrated with 1 mL methanol and 1 mL distilled water. The column was washed with 1 mL 5% methanol and eluted with 1 mL methanol. The elute was dried under nitrogen flow and dissolved in 100 μL solvent A/B (30% : 70%, v/v) for LC-MS/MS. 10 μL sample was analyzed by a Waters LC-MS/MS unit; ACQUITY UPLC BEH HILIC, 1.7 μm, 2.1 mm I.D. × 100 mm (Milford, MA) was used at a flow rate of 0.3 mL/min by linear gradient elution (solvent A : solvent B = 30% : 70%, v/v, solvent A: 0.1% TFA, solvent B: acetonitrile) using electrospray ionization for Xevo TQ MS (Waters, MA, USA).