Monitoring the Epoxidation of Canola Oil by Non-aqueous Reversed Phase Liquid Chromatography/Mass Spectrometry for Process Optimization and Control

Non-aqueous reversed phase liquid chromatography/electrospray mass spectrometry (NARP-LC/ESI-MS) was used to monitor the epoxidation of canola oil by performic acid. The reaction was sampled at regular intervals over 28 h and analyzed by NARP-LC/ESI-MS in order to observe the formation of partially epoxidized reaction intermediates and the fully epoxidized products. The experiment focused on the transformation of triacylglycerols (TAG) with 54 carbons in the fatty acyl chains and between 2 and 7 double bonds which account for > 93 % of the oil. NARP-LC/ESI-MS allowed determination of the time required for full epoxidation of the oil. It was shown that complete epoxidation of TAG with low numbers of double bonds occurs more rapidly than for those with many double bonds. Furthermore, it was observed that epoxidation of multiply unsaturated TAG occurs via a sequential process in which partially epoxidized intermediates are consumed to form other more highly epoxidized compounds as the reaction proceeds. Data obtained by flow-injection ESI-MS was found to be comparable to that obtained from NARP-LC/ESI-MS for monitoring intermediates and products and could be adapted for in-process reaction monitoring.