Structural identification of m/z 782 as 16:0a/5-HETE-PC with the use of MS/MS. (A) Negative LC/MS/MS of m/z 782→319 and 782→115 from ionophore-activated neutrophil lipid extract. (B) Negative MS/MS spectrum of m/z 782 at 23.8 minutes from neutrophil lipid. (C) Negative MS/MS spectrum of m/z 782 generated by 5-LOX oxidation of 16:0a/20:4-PC, eluting at 23.8 minutes. (D) Positive MS/MS of m/z 782, eluting at 23.8 minutes from neutrophil lipids. (E) Positive MS/MS of m/z 782 generated by 5-LOX oxidation of 16:0a/20:4-PC, eluting at 23.8 minutes.