Abstract
By using carbon-13 (13C) nuclear magnetic resonance (NMR) spectrometer, we have developed a easy quantitative method for determining the molar ratio of partial acylglycerines <1, 2-diacylglycerine (DG), 1, 3-DG, 1-monoacylglycerine (MG), and 2-MG> to triacylglycerine (TG) and/or glycerin. For refinement of some measurement conditions, we set the five kinds of palmitoyl acylglycerines (TG, 1, 2-DG, 1, 3-DG, 1-MG, and 2-MG) and glycerine as model compounds. After examining the solubility of these model compounds, we decided that pyridine-d5 was suitable as an NMR measuring solvent. We also set the delay time of the pulse repeating at 15s, which is five times longer than the longest spin-lattice relaxation times (T1) of proton (1H) NMR signals of the glycerine moieties protons and 13C NMR signals of the glycerine moieties carbons. Good agreement was observed between the result of the 13C NMR and that of the reverse-phase high performance liquid chromatography (HPLC) by the model compounds. When the characteristic peaks are quantitatively measured in 13C NMR of the commercial diacylglycerins product, each molar ratio of the derivatives, such as TG, 1, 2-DG and 1, 3-DG, can easily be determined.
