Analysis of phosphatidylcholine oxidation products in human plasma using quadrupole time-of-flight mass spectrometry.

We report here an application of the previous method for the analysis of phosphatidylcholine (PC) and lysophosphatidylcholine (lysoPC) oxidation products in human plasma using quadrupole time of flight (Q-TOF) mass spectrometry with electrospray ionization. We separated these products using an HPLC C8 column with a gradient of methanol and 10 mM aqueous ammonium acetate. Monohydroperoxides, epoxyhydroxy derivatives, oxo derivatives, and trihydroxides of palmitoyl-linoleoyl (C16:0/C18:2) PC and stearoyl-linoleoyl (C18:0/C18:2) PC were detected mainly as MH+ and [M+Na]+ ions in the plasma of alcoholic patients. Using standard synthetic PC-OH (C16:0/C18:2-OH), the lipid extract component was identified as (C16:0/C18:2-OH) PC based on the product ions of ESI-MS-MS. Using standard synthetic PCOOH (C16:0/C18:2-OOH) as a reference, the PCOOH concentration in plasma was quantified. Two oxidatively modified lysoPCs were also detected. This is the first report showing the presence of epoxyhydroxy derivatives, monohydroperoxides, oxo derivatives, and trihydroxides of (C16:0/C18:2) PC and (C18:0/C18:2) PC, and PC-OH (C16:0/C18:0-OH) in human plasma.