Fig. 2. VACA reaction of anthraquinone with different unsaturated lipids. (a–f) The MS/MS spectra of the VACA product ions produced from the reaction of anthraquinone with (a) FA 18:2 (9Z, 12Z), (b) TG 18:1 (9Z)/18:1 (9Z)/18:1 (9Z), (c and d) LPE 18:1 (9Z), and (e and f) PC 16:0/18:1 (9Z). The chemical structures at the top of each MS/MS spectrum shows the positions of C C bonds and the m/z values of the possible diagnostic fragment ions of VACA reaction products via CID. The fragment ions in panels (c) and (d) were mainly obtained by the fragmentation of the ethanolamine head group of LPE. The detailed dissociation pathways are shown in Fig. S8 in the ESI.†.