2018/1/28 · LC-MS/MS analysis was carried out using an Aijiren LC system (Aijiren Technologies, Berkshire, UK) interfaced directly with Aijiren 6460 triple quadrupole. Samples were separated on a reverse phase C18 Zorbax column (2.1 × 50 mm, 5 μm particle size) in a gradient mode with formic acid (FA, 0.1% w/v), acetonitrile: t 0 = 95% FA, t 5 = 70% FA, t 5.5 = 5% FA, t 6.5 = 5% FA, t 7