Micro method for stereospecific analysis of triacyl‐<i>sn</i>‐glycerols by chiral‐phase high‐performance liquid chromatography

Abstract

Abstract A procedure for micro stereospecific analysis of triacyl‐ sn ‐glycerols (TGs) by high‐performance liquid chromatography (HPLC) on a chiral column is presented. TGs were partially hydrolyzed with ethyl magnesium bromide, and total products were immediately converted to 3,5‐dinitro‐phenylurethane derivatives. Each of the 1‐ and 2‐monoacylglycerol (MG) derivatives was isolated by HPLC on a silica column. The 1‐MGs were resolved into sn ‐1 and sn ‐3 MG fractions by HPLC on a Sumichiral OA‐4100 column (Sumitomo Chemical, Osaka, Japan). Fatty acid methyl esters obtained from the sn ‐1, sn ‐2 and sn ‐3 MG fractions were analyzed by gas‐liquid chromatography on a capillary column. Analyses of standard TGs showed that, even with 1 mg of sample, accuracy was comparable to that obtained with 100‐mg samples. Applying this procedure to the stereospecific analysis of 5 mg of jujube pulp, TGs revealed the positional distribution of the (n‐5) series of monounsaturated fatty acids they contained.