PC profile changes during copper-induced oxidation of human LDL. Human LDL (0.2 mg/mL) was incubated with copper sulfate (5 μM) at 37°C for up to 3 h. Lipids were extracted by the Bligh and Dyer method from 10 μg of oxLDL after addition of 20 pmol of didecanoyl PC as internal standard. Total lipid extract was subjected to LC-MS/MS analysis to detect 42 PC and modified PC molecular species by MRM mode, and they were classified into five categories: PUFA-PC (A), S/MUFA-PC (B), lysoPC (C), cleaved-chain oxPC (D) and long-chain oxPC (E). The peak area (cps) for each species was normalized based on the peak areas of internal standard, and the means and SD were calculated from six independent preparations. Statistical significance of comparison with the sample without incubation (0 min) was calculated by ANOVA; *, p < 0.05; #, p < 0.01; +, p < 0.005; **, p < 0.001.