IDENTIFICATION OF FURAN FATTY-ACIDS IN HUMAN BLOOD-CELLS AND PLASMA BY MULTIDIMENSIONAL GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

The separation and determination of low-concentration furan fatty acid s in complex sample matrices, such as oils, tissue lipids or blood, pr eviously required time-consuming pre-analytical separation steps in or der to obtain sufficient resolution in single-column gas chromatograph y. By using a multi-dimensional GC-MS system, it is now possible to id entify directly the methyl esters of furan fatty acids without any fur ther pre-analytical separations. The Folch method was used to isolate the lipids from the different blood components and transesterification of total lipids was carried out by sequential saponification and este rification. Individual lipid classes were isolated by preparative TLC separation and transesterified into their methyl esters by a one-step reaction using acetyl chloride as catalyst. Furan fatty acids were fou nd in all blood samples in differing relative amounts. 12,15-Expoxy-13 ,14-dimethyleicosa-12,14-dienoic acid (F6) and 12,15-epoxy-13,14-dimet hyloctadeca-12,14-dienoic acid (F4) were detected in both red blood ce lls and in plasma; in platelets, only F6 was found. In serum, furan fa tty acids were detected only in the phospholipid fraction, and not in cholesterol esters or triglycerides.