Supercritical fluid chromatographic analysis of new crop seed oils and their reactions

Abstract

Supercritica/fluid chromatography (SFC) with an open tubular column of nonpolar stationary phase separated triglycerides from crambe, meadowfoam, Euphorbia lagascae, and vernonia oils based on their molecular weight. The triglyceride compositions were consistent with the literature. SFC proved also to be a valuable tool in analyzing lipase-catalyzed transesterification reactions where lesquerella oil and estolides were among the substrates employed. Analyte molecular weights could be estimated from a retention time-(or elution density-) molecular weight calibration curve. An increase in isothermal column temperature during SFC pressure or density programming improved the resolution of high-molecular-weight (>600 Da) analytes but yielded poorer resolution for analytes of molecular weight < 200. A simultaneous pressure and temperature ramping program proved superior in enhancing resolution in several instances.Supercritical fluid chromatography (SFC) is becoming a valuable tool in the analysis of lipids as it is replacing high-performance liquid chromatography (HPLC) and gas chromatography (GC) as the analytical tool of choice for several applications. SFC can be considered a hybrid of GC and HPLC because supercritical fluids possess properties (e.g., density, viscosity, and self-diffusion coefficient) intermediate between gases and liquids. For example, separation of analytes by relative volatility, as encountered in GC, can also be achieved with SFC but at much lower elution temperatures and without derivatization. The use of lower temperatures protects analytes that are susceptible to thermal degradation, such as polyunsaturated and oxygenated lipids. With the onset of equipment that allows addition of modifiers to the supercritical fluid mobile phase, HPLC-Iike separations can be achieved by SFC, but a larger range of detectors--GC-style

A detailed triglyceride analysis ofLesquerella fendleri oil: Column chromatographic fractionation followed by supercritical fluid chromatography

“…A program that simultaneously increased column pressure and temperature was found to be superior in separating lesquerella oil TG based on molecular weight. This program and the equipment used are described elsewhere (5). To elucidate the location of C18 hydroxy acyl groups in oil fraction IX, a small sample was subjected to lipolysis with a 1,3-specific lipase, as described previously (2).…”

Supercritical fluid chromatography for lipid analysis in foodstuffs

“…SFC allows for the analysis of high molecular or thermally labile TAGs, in relatively short times and without any pre-derivatization step. Most of the early studies focused on TAGs used cSFC, with both polar (e.g., cyanopropyl-phenyl-methylpolysiloxane, polyethyleneg-lycol) and nonpolar (e.g., phenyl-methylsiloxane, polymethylsiloxane) stationary phases [78][79][80][81][82][83][84][85][86][87]. The possibilities of both cSFC and pSFC in the analysis of lipids have been nicely illustrated by David et al [112], as well as key applications of both methodologies carried out in the authors' laboratories.…”

Supercritical Fluid Chromatography and Extraction

“…SFC is clearly well suited to the characterization of seed and crop oils (134)(135)(136)(137)(138). Borch-Jensen et al used a variety of chromatographic techniques to study seed oils and found that SFC was most versatile for studying both the free fatty acids and the intact oils (134).…”