Simultaneous gas chromatographic determination of concentration and isotopic enrichment of fatty acids in human plasma using flame ionization and mass spectrometric detection

Free fatty acids (FFAs) are important not only because they provide substra te for oxidation but also because they have the potential to regulate sever al metabolic and hormonal processes. Using stable isotope tracers, these pr ocesses can be studied. Here we present a gas chromatographic method to mea sure FFA concentrations and enrichments after extraction from plasma and su bsequent derivatization in one analytical run, using both flame ionization and mass-selective detection. For concentration determinations intra-assay variation ranged from 1.5 to 4.9%, inter-assay variation ranged from 3 to 1 1%. Intra- and inter-assay variations of the enrichment determination of pa lmitic acid were 1.4 and 0.9%, respectively. (C) 2001 Elsevier Science BN. All rights reserved.