Preparative thin-layer chromatographic separation and subsequent gas chromatographic-mass spectrometric analysis of monoacylglycerols derived from butter oil by fungal degradation.

A semi-micro method has been developed using preparative thin-layer chromatography (TLC) to separate acylglycerols for the subsequent analysis by gas chromatography-mass spectrometry (GC-MS). Monoacylglycerols (MAGs) were formed from butter oil by fungal degradation with Penicillium roquefortii. Total lipids were extracted with hexane-2-propanol (3:2, v/v) and separated on silica gel preparative TLC plates with fluorescence indicator (Merck). The plates were developed in hexane-diethyl ether-formic acid (80:20:2, v/v). Lipid bands were detected under UV light or with iodine vapour, removed and then extracted with hexane-2-propanol (3:2, v/v). The MAG band (RF 0.03) was silylated into trimethylsilyl (TMS) ethers. Structures and composition of MAG-TMS ethers were analysed by GC and GC-MS. Formation of characteristic ions for the identification of sn-1(3)- and sn-2-MAG isomers was discussed. The method is simple, inexpensive and powerful for the separation and analysis of relatively small amounts of MAGs (0.2-5.0 mg) formed from fungal degradation.