Identification and Quantification of the Molecular Species of Acylglycerols in Castor Oil by HPLC Using ELSD

Abstract

Sixteen molecular species of acylglycerols (AG) in castor oil have been identified and quantified. Evaporative light scattering detection (ELSD) responses of different amounts of the standards of molecular species of AG were nearly linear and similar. In general, the addition of a double bond and a hydroxyl group on the acyl chain and the shortening of the acyl chain decreased the ELSD response of AG slightly. The quantification of molecular species of AG was based on the percentage peak area in the HPLC chromatogram. Triricinolein (RRR) constituted about 71% of castor oil. The contents of the molecular species of diricinoleoyltriacylglycerol (RR‐TAG) were, in total, about 18% and were in the order of RRO (8.8%), RRL (6.6%), RRS (1.1%), RR‐lesqueroleate (0.67%), RRP (0.47%) and RRLn (0.15%). The level of R‐TAG was about 0.3%. The level of TAG containing no ricinoleate was less than 0.1%. Diricinoleoylglycerol, a diacylglycerol, was also identified and quantified (0.14%) in castor oil.