A SEMIMICRO METHOD FOR STEREOSPECIFIC ANALYSIS OF TRIGLYCERIDES

The precision of the methods for the stereospecific analysis of triglycerides devised by Brockerhoff1,2 has been investigated. A modified procedure has been developed which is capable of considerable accuracy with 10-40 mg of triglyceride or less. α,β-Diglycerides are prepared by reaction of the triglycerides with ethyl magnesium bromide in diethyl ether. These are converted synthetically to phospholipids which are hydrolysed by the stereospecific phospholipase A of snake venom. The fatty acid composition of the resulting lysophosphatide accurately represents that of the 1-position of the original triglyceride. The fatty acid composition of the 2-position must be determined independently by pancreatic lipase hydrolysis so that the composition of the 3-position can then be calculated. Alternative methods for determining the composition of the 2- and 3-positions are available. Application of the method to synthetic 2-oleo-distearin, two pig depot fats and maize oil is decribed. © 1969.