Glycerides column chromatography

The solvent extracts can be cleaned up by traditional column chromatography or by solid-phase extraction cartridges. This is a common cleanup method that is widely used in biological, clinical, and environmental sample preparation. More details are presented in Chapter 2. Some examples include the cleanup of pesticide residues and chlorinated hydrocarbons, the separation of nitrogen compounds from hydrocarbons, the separation of aromatic compounds from an aliphatic-aromatic mixture, and similar applications for use with fats, oils, and waxes. This approach provides efficient cleanup of steroids, esters, ketones, glycerides, alkaloids, and carbohydrates as well. Cations, anions, metals, and inorganic compounds are also candidates for this method [7],... 

The concentration of biodiesel (fetty acid methyl esters) and glycerides were analyzed by liquid chromatography (Shimadzu-lOA HPLC). An ODS-2 column (250x4.6mm) was used for the separation. The flow rate of the mobile phase (acetone acetonitrile=l l) was set to 1 ml/min. Peaks were identified by comparison with reference standards. Standards of methyl esters, monoglycerides, digjycerides and triglycerides were bought from Fluka. 

Figure 2.8 Supercritical fluid chromatography, with use of a miniaturized evaporative lightscattering detector, of seed extracts from (a) an autumn rapeseed (b) Camelina sativa (triacyl-glycerides containing long-chain monoenes have not been identified because reference substances are not available). SFE/SFC was off-line. Column as in Fig. 2.2. Separation conditions temperature 140°C pressure 160 atm, after 1 min programmed at -10°Cmin to 100°C and 25 atm min" to 260 atm, then programmed at -l°Cmin to 75°C and at 2 atm min to 260 atm. Extraction conditions temperature 90°C, pressure 160 atm. Abbreviations L = linoleate Ln = linolenate 0 = oleate P = palmitate S = stearate SFC = supercritical fluid chromatography SFE = supercritical fluid extraction.

Glycerides can be analyzed by high-temperature GC on low-bleed columns (Fig. 7). Care should be taken during sample preparation to avoid transesterification. Derivatization is required for good chromatography of free fatty acid and the mono- and diesters, especially if the column is not new. Triesters are not affected by the derivatization reaction. Elution is in the order derivatized fatty acids, derivatized monoesters, derivatized diesters, and triesters (88). 

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