Figure 2. Optical image of tissue and mass spectrometry data of major lipid at m/z 760.6 from mouse optic nerve. A: Optical image of ocular tissue section coated with the 2,5-dihydroxybenzoic acid matrix. B: Matrix-assisted laser desorption ionization–imaging mass spectrometry (MALDI-IMS) image in positive ion mode at 10 µm spatial resolution of a mouse optic nerve section illustrating the distribution and intensity of a protonated phosphatidylcholine lipid at m/z 760.6. C: Product ion spectrum of the lithiated form of m/z 760.6 (m/z 766.6) produced from Fourier transform ion cyclotron resonance mass spectrometer analysis identified as C₄₂H₈₂NO₈P (PC(16:0/18:1)).