An optimized method for fatty acid analysis, including quantification of trans fatty acids, in human adipose tissue by gas-liquid chromatography

Considering the need for a quick direct method for measurement of the fatty acid composition including trans isomers ofhuman adipose tissue we have developed a procedure using gas-liquid chromatography (GLC) alone, which is thussuitable for validation of fatty acid status in epidemiological studies. Fatty acids ranging in carbon number from 12 to 22and with 0-6 double bonds were resolved and identified by capillary column GLC with a temperature program starting at150 degrees C. Following injection, the oven temperature was increased at a rate of 3 degrees C/min to 200 degrees C,then held constant for 25 min, and finally raised at 25 degrees C/min to 225 degrees C. The trans and cis isomers of18:1 were well separated from each other, as shown by silver-ion thin-layer chromatography. Verification by standardsshowed that the trans 18:1 isomers with a double bond in position 12 or lower were separated from the cis 18:1 isomerswith a double bond in position 6 or higher. As the adipose tissue samples contained only small amounts of the 13t-, 14t-and 15t-18:1 isomers and the 4c- and 5c-18:1 isomers the overlapping was found to be minimal. The GLC method mayalso be valuable for determining the fatty acid profiles including total trans in other tissues.