High field 13C NMR spectroscopic analysis of the triacylglycerols of Jatropha curcas oil

Abstract

Gated decoupled ¹³C NMR has been employed to determine the acyl composition and acyl positional distribution on the glycerol backbone in the triacylglycerols of Jatropha curcas oil. Results revealed the presence of saturated, oleic and linoleic acids in the oil. Integrals obtained from the allylic carbons were used for semiquantitative analysis of the oil and gave the percentage of total saturated, oleic and linoleic acids in the oil as 27, 41 and 32, respectively. The results obtained by ¹³C NMR compared favourably with those obtained by gas chromatographic analysis. Analysis of the spectra further revealed that the saturated acyl esters are randomly distributed in the a and b glyceridic positions, with oleic being approximately 60% distrbuted at a glyceridic carbons and linoleic approximately 52% distributed at b glyceridic carbon.

KEY WORDS: Gated decoupled 13C NMR, Acyl composition, Acyl positional distribution, Triacylglycerols, Jatropha curcas oil

Bull. Chem. Soc. Ethiop. 2004, 18(1), 59-65.