Abstract

Non-esterified and triacylglyceride fatty acid quantification in plasma is important in order to know fatty acid plasma availability and the nutritional status. A reliable method to determine free, triacylglycerol, phospholipid, and cholesterol ester fatty acids in human plasma samples by combining two types of fatty acid isolation and enzymatic and chromatographic methods has been developed and made safer by avoiding diazomethane derivatization. Lipoprotein lipase was used to obtain hydrolyzed fatty acids from triacylglycerides, and chromatography performed with an active carbon column was used to isolate free fatty acids. Posterior safe derivatization to methylated fatty acids by transesterification, with m-trifluoromethylphenyl trimethylammonium hydroxide reagent (Meth-Prep (TM) II) and gas chromatography enabled us to identify and quantify a wide spectral range of non-esterified and triacylglyceride fatty acids in plasma. Additionally, the method allows the fatty acids of the phospholipid and cholesterol ester fraction to be determined after the determination of total plasma fatty acids. Determining the individual fatty acid recovery with respect to the C17:0 internal standard makes it possible to calculate the individual fatty acid concentration in each fraction of plasma. The method optimizes the derivatization reagent and chromatographic conditions and enables quantification of additional fatty acids such as omega-3 and omega-6 of the C18:3 fatty acid and C20:1n9, C22:0, and C22:6n3 fatty acids. The procedure can be safely used to analyze a large number of samples.