Capillary gas chromatography of underivatized fatty acids with a free fatty acid phase column and a programmed temperature vaporizer injector.
Underivatized fatty acids occurring in lipids of a number of biological specimens (blood plasma, tissues, food) were studied using a capillary column with a chemically bonded free fatty acid phase and a programmed temperature vaporizer. Non-linear calibration dependences were obtained for almost all the acids at lower concentrations because of losses in the column, non-linearity increasing with increasing carbon number and degree of unsaturation. Sample introduction at temperatures below the solvent boiling point eliminates losses in the injector. The lower recovery of long-chain polyunsaturated acids is caused by interactions occurring in the column. Some critical pairs remain unresolved in the underivatized form (18:1n9-18:1n7, 20:4n6-20:3n3), whereas the corresponding methyl esters exhibit baseline resolution.
Department of Analytical Chemistry, Faculty of Natural Sciences, Charles University, Prague, Czech Republic.
J
J
Vicanová
E
E
Tvrzická
K
K
Stulík
D002849:Chromatography, Gas; D005227:Fatty Acids / Q000032:analysis* / Q000097:blood / Q000737:chemistry; D005230:Fatty Acids, Nonesterified / Q000737:chemistry*; D005504:Food Analysis; D006801:Humans; D010713:Phosphatidylcholines / Q000097:blood; D013696:Temperature
D005227:Fatty Acids; D005230:Fatty Acids, Nonesterified; D010713:Phosphatidylcholines