Glycidyl oleate

Glycidol (purity 96.0%) and fluorescein isothiocyanate (FITC; purity ≥ 90.0%) were obtained from Sigma-Aldrich (St. Louis, MO, USA). Glycidyl oleate was purchased from FUJIFILM Wako Pure Chemical Corporation (Osaka, Japan). L-d₈-valine (purity 98.0%), which was used for the synthesis of the Glycidol internal standard 3-(fluorescein-5-yl)-1-(2,3-dihydroxypropyl)-5-d₇-isopropyl-2-thioxo-4-imidazolidinone (DHP-Val-d₇-FTH) [12 (link)], was obtained from Cambridge Isotope Laboratories, Inc. (Tewksbury, MA, USA). Lipase Kit S was obtained from DS Pharma Biomedical Co., Ltd. (Osaka, Japan). All other chemicals and solvents used were of analytical grade.

The standard materials of glycidyl palmitate (C16:0-GE, purity 98.0%), glycidyl stearate (C18:0-GE, purity 98.0%), glycidyl oleate (C18:1-GE, purity 98.0%), glycidyl linoleate (C18:2-GE, purity 90.0%), glycidyl linolenate (C18:3-GE, purity 85.0%), 3-MCPD di-palmitate (purity 95.0%), 3-MCPD di-stearate (purity 98.0%), 3-MCPD di-oleate (purity 98.0%), 3-MCPD dilinoleate (purity 98.0%), and 3-MCPD di-linolenate (purity 98.0%) were purchased from Wako Chemicals (Osaka, Japan). The standard solutions of the 3-MCPDEs and GEs (0.01–10 ppm) were diluted with methanol (Kanto Chemical Co., Inc., Tokyo, Japan)/2-propanol (Wako Chemicals) (1:1 v/v) and used for liquid chromatography-tandem mass spectrometry (LC-MS/MS). All other reagents used in this study were of analytical grade.