Fundamental Sessions
Day 1, June 10（Wed.） 16:42-17:00 Room D (5F 511+512)
- 1D-O2-1642
Visualizing the Spatial Distribution of Metabolites in Banana Tissue by Graphite Carbon Black-Assisted Laser Desorption Ionization-Mass Spectrometry Imaging
(1Kyushu Univ., 2KISTEC, 3Kyoto Univ., 4NII, 5Chuo Univ.)
oZhuofei Liu1, Yuzuki Koga1, Miho Sase2, Hiroki Okawa2, Takenobu Ogawa3, Imari Sato4, Yukio Kawano2,5, Toshiro Matsui1, Mitsuru Tanaka1
Food flavor is determined by odor- and taste-active compounds whose spatial distribution within the tissues influences sensory perception. Conventional analytical methods require extensive pretreatments that disrupt native localization, which matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) imaging enables in situ visualization of analytes but suffers from strong background interference in the low m/z region. To address these challenges, we develop a reproducible graphite carbon black (GCB)-assisted LDI-MS imaging method using an optical density (OD)-assisted spraying control strategy. OD values showed a strong linear correlation with the deposited GCB amount. Optimal performance was achieved at OD 200±4, providing the highest signal intensity in both ion modes. Compared with conventional cycle-fixed spraying, the OD-assisted method improved reproducibility and reduced variation in the relative intensity of [13C5, 15N]glutamate. Under the optimized conditions, GCB-assisted LDI-MS imaging detected more MS signals than MALDI-MS imaging (98 in positive mode; 111 in negative mode). Several flavor-related metabolites, including sugars, amino acids, organic acids, and phenolic acids, were clearly visualized, and metabolic changes during ripening were successfully mapped. In conclusion, GCB-assisted LDI-MS imaging enables reliable and comprehensive visualization of the spatial heterogeneity and temporal evolution of flavor-related metabolites in food tissues.