Kalo P, Kemppinen A, Kilpeläinen I
Department of Applied Chemistry and Microbiology, University of Helsinki, Finland.
Lipids. 1996 Mar;31(3):331-6. doi: 10.1007/BF02529880.
Positional isomers (1-butyryl-2X-3Y-rac-glycerol and 2-butyryl-1X-3Y-rac-glycerol; X,Y = long-chain acyls) of saturated triacylglycerols (TAG) within 34 and 40 acyl carbons were shown to separate in two chromatographic peaks on immobilized phenyl(65%)methylsilicone column by gas-liquid chromatography, and on reversed-phase ODS-1 column by high-performance liquid chromatography. The analysis of 500-MHz 1H nuclear magnetic resonance (NMR) spectra showed distinct differences between 2-butyryl-1X-3Y-rac-glycerol and 1-butyryl-2X-3Y-rac-glycerol isomers in the resonance signals of methylene and methine protons of glycerol backbone, and carbon-2 methylene of acyl groups, and methyl protons of butyryl group. The 1H NMR spectra of three interesterified mixtures of three monacid TAG containing saturated butyrate and caproate TAG and unsaturated butyrate TAG showed that triplets of methyl protons of butyryl groups at sn-1(3)- and sn-2-positions in saturated and unsaturated TAG had similar chemical shifts and that the chemical shift of caproyl methyl protons was different from those of butyryl methyl protons. The positional distribution of butyryl groups in isolated positional isomers of butyrate TAG, interesterified TAG mixtures, and natural and interesterified butteroil can be determined by integration of these signals.
含有34至40个酰基碳的饱和三酰甘油（TAG）的位置异构体（1-丁酰基-2X-3Y-外消旋甘油和2-丁酰基-1X-3Y-外消旋甘油；X、Y = 长链酰基）通过气液色谱法在固定化苯基（65%）甲基硅氧烷柱上以及通过高效液相色谱法在反相ODS-1柱上可分离为两个色谱峰。500兆赫兹的1H核磁共振（NMR）光谱分析表明，2-丁酰基-1X-3Y-外消旋甘油和1-丁酰基-2X-3Y-外消旋甘油异构体在甘油主链的亚甲基和次甲基质子、酰基的碳-2亚甲基以及丁酰基的甲基质子的共振信号上存在明显差异。三种含有饱和丁酸酯和己酸酯TAG以及不饱和丁酸酯TAG的单酸TAG的三种酯交换混合物的1H NMR光谱表明，饱和和不饱和TAG中sn-1(3)-和sn-2-位丁酰基的甲基质子三重峰具有相似的化学位移，且己酰基甲基质子的化学位移与丁酰基甲基质子的不同。通过对这些信号进行积分，可以确定丁酸酯TAG的分离位置异构体、酯交换TAG混合物以及天然和酯交换乳脂中丁酰基的位置分布。
