Chromatographic and spectroscopic methods in the analysis of triacylglycerol species and regiospecific isomers of oils and fats.

The chromatographic, spectrophotometric, and spectroscopic methods usually used for the analysis of oils and fats are reviewed, with special attention to the detection, identification, and quantitation of the triacylglycerol species present in the most common edible vegetable oils. Also, a review of the methods used for the identification of the regiospecific types of the triacylcglycerol species of oils and fats is presented. Methods of high-performance liquid chromatography in the normal, reversed, silver ion, size exclusion, and chiral modes of thin layer chromatography in the normal, reversed, and silver ion modes of supercritical fluid chromatography with capillary glass or stainless steel columns of capillary gas chromatography and of mass spectrometry in different modes are presented and evaluated. The different sample pretreatment methods, the chromatographic columns, the elution systems, and the detectors and detection modes that have been combined with the above methods are also reviewed. Other spectroscopic methods used for the characterization of the status of an oil or fat, such as ultraviolet, fluorescence, chemiluminescence, infrared, and nuclear magnetic resonance are also reported, selectively. The majority of the triacylglycerol species present in an oil or fat could be analyzed and identified by a particular technique of the reviewed methods, but a complete separation in one single run requires a combination of two or more of the existing techniques, especially for samples with high triacylglycerol species variability.