PMR analysis of unsaturated triglycerides using shift reagents.

The addition of Pr(fod)3 i.e. tris(1,1,1,2,2,3,3-heptafluoro-,7-dimethyl 1-4,6-octanedionato) praseodymium, to trilinolein has been found to induce a difference in the chemical shifts of the absorptions from the acids on the alpha- and beta positions. At 220 MHz this was observed up to 18 carbon atoms along the chain. Decoupling of the alkenyl protons at 100 MHz enabled the absorptions from the skipped methylene groups to be used to determine the position of linoleate and linolenante chains in triglycerides.