Detection of phosphatidylcholine oxidation products in rat heart using quadrupole time-of-flight mass spectrometry

An improved technique for the analysis of phosphatidylcholine (PC) and lyso-phosphatidylcholine (lyso-PC) oxidation products was developed 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. Monohydroxides, oxo derivatives, and trihydroxides of palmitoyl-linoleoyl (C16:0/C18:2) PC, stearoyl-linoleoyl (C18:0/C18:2) PC, and oleoyl-linoleoyl (C18:1/C18:2) PC were detected mainly as MH+ and [M + Na]+ ions in the heart of the intact rat. 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 and, the PC-OH concentration was quantitated. Four oxidatively modified 1-lyso-phosphatidylcholines (lyso-PCs) were also detected. This is the first report showing the presence of monohydroxides, oxo derivatives, and trihydroxides of (C16:0/C18:2)PC, (C18:0/C18:2)PC, and (C18:1/C18:2) PC in the rat heart.