Synthesis of sodium cis-12,13-epoxy- cis-9-octadecenyl sulfonate from Vernonia oil, and comparative quantitative fatty acid analysis of triacylglycerols using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and gas chromatography.

摘要

A water soluble, high-foaming epoxyalkene sulfonate, sodium cis-12,13-epoxy-cis-9-octadecenyl sulfonate, has been synthesized from methyl cis-12,13-epoxy-cis -9-octadecenoate by a series of simple reactions that include lithium aluminum hydride reduction, tosylation, and SN2 reactions. The sulfonate is a new compound that belongs to a very important class of industrial chemicals known as surfactants that are used in a myriad of commercial products and processes ranging from personal care products to oil drilling. The overall yield of the epoxyalkenesulfonate was 62%.;Quantitative analysis of fatty acids from five triacylglycerol products—coconut oil, palm kernel oil, palm oil, lard, and cocoa butter—were carried out with two analytical methods: matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS), and gas chromatography (GC), in an effort to validate the application of MALDI-TOFMS in quantitative fatty acid analysis. For the GC analysis, transmethylated products were used, whereas, for the MALDI-TOF analysis, saponified products were used. Under MALDI-TOF conditions, the acids were detected as sodiated sodium carboxylates [RCOONa + Na]+ consistent with a mode of ionization that was previously reported.;Thus, MALDI-TOF spectrum of saponified coconut oil showed the presence of sodiated sodium salts of caprylic acid (7.5% ± 0.67); capric acid (6.9% ± 0.83); lauric acid (47.8% ± 0.67); myristic acid (20.4% ± 0.51); palmitic acid (9.8% ± 0.47); linoleic acid (0.9% ± 0.07); oleic acid (4.8% ± 0.42); and stearic acid (2.0% ± 0.13). Saponified palm kernel oil had a fatty acid profile that include caprylic acid (3.5% ± 0.59), capric acid (4.7% ± 0.82), lauric acid (58.6% ± 2.3), myristic acid (20.9 ± 1.5), palmitic acid (7.2% ± 1.1), oleic acid (3.8% ± 0.62), and stearic acid (1.2% ± 0.15).;Quantitative gas chromatographic analysis of the corresponding methyl esters from these triacylglycerol products yielded data that was mostly in agreement with the MALDI-TOFMS data. MALDI-TOF experiment, however, proved to be superior to the GC experiment particularly with regard to baseline resolution of unsaturated acids. Furthermore, the ability of MALDI-TOFMS to detect low concentrations of fatty acids rendered it more sensitive than the GC methodology.