Imaging and Identification of Phospholipids in Mouse Liver Tissue by Matrix-Assisted Laser Desorption Ionization-Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Matrix-assisted laser desorption/ionization-fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR MS)-based mass spectrometric imaging (MSI) was applied to profile and identify phospholipid molecules in mouse liver tissues, which were cut into tissue sections (7 μm) by a cryostat at −20°C and covered with 7 g L−1 of alpha-cyano-4-hydroxycinnamic acid as matrix in 50% methanol/0.2% trifluoroacetic acid solution. 13 phospholipid compounds, which are classified as 5 different classes, phosphatidic acid, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidylserine, were accurately identified. Their molecular weights are between 700 and 900 Da. The results indicate that MALDI-FTICR MS-based MSI is a powerful tool to explore the distributions of disease-related molecules and drug metabolites in tissues.