Quantification of fatty acids has been crucial to elucidate symbiosis relationship between ants and plants. The target plant for analysis is Hylomecon Hylomeconoides, a Korean endemic species with elaiosome part. In the previous studies, elaiosome have quantitatively analyzed the total amounts of fatty acyls which compose lipid and free fatty acids using derivatization and GC-FID or MS instrument. Therefore, the quantification method for the elaiosome have been optimized using GC-MS in our laboratory. Besides analysis of total fatty acids, the analysis of free fatty acids and plant lipidomics have been proceeded using HPLC-ESI-Q-TOF and UPLC-ESI-Triple Quadrupole instrument, respectively.