N 2 3 dihydroxypropyl 13c5 valine

Glycidol (98%, CAS No. 556-52-5) was purchased from Acros Organics (Geel, Belgium). L-Valine-(¹³C₅) (96–98% purity), RS-glyceraldehyde and sodium cyanoborohydride, used for the synthesis of the internal standard N-(2,3-dihydroxypropyl)-(¹³C₅)valine, were obtained from Cambridge Isotope Laboratories, Inc (Tewksbury, MA, USA) and Sigma Aldrich (St Louis, MO, USA) respectively. Cyanoacetic acid and ammonium hydroxide were purchased from Fluka (Buchs, Switzerland). The analytical standard used for the calibration curve, fluorescein thiohydantoin of N-(2,3-dihydroxypropyl)valine (diHOPrVal-FTH), was synthesized previously within the research group [15 (link)]. Fluorescein isothiocyanate (FITC) was purchased from Karl Industries (Aurora, OH, USA) and potassium hydrogen carbonate (KHCO₃) from Merck (Darmstadt, Germany). All other chemicals (analytical grade) were obtained from Sigma Aldrich (St Louis, MO, USA).

Fluorescein isothiocyanate (FITC), glycidol, (±)-3-chloro-1,2-propanediol (3-MCPD) (purity 98.0%), and glycidyl oleate (purity 98.0%) were obtained from Sigma-Aldrich (St Louis, MO). Epichlorohydrin, propylene oxide, 1-bromopropane, allyl alcohol, D(-)-fructose, and DL-glyceraldehyde were obtained from FUJIFILM Wako Pure Chemical Industries Ltd. (Osaka, Japan). L-Valine-(¹³C₅) (purity 98.0%) used for the synthesis of the internal standard N-(2,3-dihydroxypropyl)-(¹³C₅)valine, were obtained from Cambridge Isotope Laboratories, Inc. (Tewksbury, MA, USA). All other chemicals and solvents used were analytical grade.