SCIENTIFIC AND PRACTICAL ASPECTS OF DEVELOPING THE EXPRESS METHOD FOR DETERMINATION OF CYST AND TRANS ISOMERS

Abstract

The article presents the study of methyl esters of cis- and trans-isomers of fatty acids by the most common method of quality control in the oil and fat industry – gas-liquid chromatography using analytical columns from leading manufacturers (Agilent Technologies, Supelco, Phenomenex). The effectiveness of the chromatographic method of fatty acid analysis using columns HP-88, SP-2380, Zebron-FAME in the absence of data on the composition of the stationary phase, which depends on the geometric parameters of the columns and the quality of sample preparation. Optimal separation conditions for fatty acid methyl esters, including their isomers, were confirmed by column calibration with a standard mixture of fatty acid methyl esters. Data from studies of the resolution of analytical columns using a sample of a mixture of methyl esters of fatty acids 37 Component FAME Mix, etc. Supelco USA (cat. № 47885-U) and experimentally found the best resolution of the critical pair C18: 3-C20: 1 peak, which merge with the time of operation of the column. The minimum analysis time of fatty acid methyl esters to 36.2 minutes was determined by selecting the carrier gas flow and the temperature gradient of the Zebron-FAME column thermostat, which significantly reduces the duration of the study by gas-liquid chromatography, which is the reference. It was found that over time, the use of sodium methylate on the chromatogram of methyl esters of fatty acids appear peaks of acylglycerols, which significantly affect the resolution of the chromatographic columns and adversely affect the final result. It has been experimentally determined that the shelf life of sodium methylate, which provides high quality chromatographic analysis, is one month.