Comparison of two methods for the determination of fatty acid profiles in plasma and erythrocytes

Abstract

We have validated and compared two methods for the determination of fatty acid profiles in biological samples by capillary gas chromatography. Method I consisted of a previous lipid extraction and esterification of fatty acids using boron trifluoride-methanol. Method II was a direct method that combined extraction and esterification of freeze-dried samples in a single step, using acetyl chloride as the reagent. The two methods were applied to the analysis of plasma and erythrocyte samples. Both methods gave similar results in plasma, whereas in erythrocytes, the direct method gave significantly higher contents of total fatty acids. Precision and recovery rates were determined and the results were satisfactory. Detection and quantification limits showed that both methods had excellent sensitivity. It was concluded that the direct method has substantial advantages over the conventional method, such as higher values in erythrocytes, rapidity and less possibility of contamination or fatty acid losses. Therefore, it is preferable for the analysis of biological samples such as plasma and erythrocytes.

Dietary fish oil n-3 polyunsaturated fatty acids and alpha-linolenic acid differently affect brain accretion of docosahexaenoic acid and expression of desaturases and sterol regulatory element-binding protein 1 in mice☆

“…Tissues were first hand homogenized in sodium chloride solution (145 mM) (1:5, wt/vol). Fatty acid methyl esters (FAMEs) from plasma and tissue homogenate were prepared according to a modified method of Lepage and Roy [22,23]. Briefly, 2 ml of methanol-n-hexane (4:1, vol/vol) solution containing C15:0 (an internal standard) and 2 μl of BHT (20 mM) were added to 100 μl of plasma or tissue homogenate to prevent lipid oxidation, then 0.2 ml of acetyl chloride was slowly added.…”

Improved Extraction of Saturated Fatty Acids but not Omega‐3 Fatty Acids from Sheep Red Blood Cells Using a One‐Step Extraction Procedure

“…The differential analysis of fatty acids from sheep RBC using the one-step compared with the two-step procedure observed in the current study agrees with previous findings examining the extraction of lipids from a range of tissues. The concentration of a number of fatty acids, in particular SFA, was higher in human RBC [12], milk [24] and plasma [11] when lipids were extracted and FAME were analysed using the one-step procedure compared with extraction of lipid using the Folch procedure.…”

“…The efficiency of extraction of lipid and analysis of fatty acid methyl esters (FAME) from RBC may be differentially affected by the method of lipid extraction. The analysed concentrations of C16:0 and C18:0 but not C18:2n-6 and C20:5n-3 were significantly higher when fatty acids were analysed in the RBC of humans using the one-step procedure of Lepage and Roy compared with extraction using the Folch procedure [12]. This differential extraction may influence the results obtained when examining the effects of dietary treatments on changes in RBC fatty acid profiles.…”

Effect of a low-fat diet enriched either with rapeseed oil or sunflower oil on plasma lipoproteins in children and adolescents with familial hypercholesterolaemia. Results of a pilot study

“…Furthermore, fatty acid composition of plasma phospholipids was analyzed using gas chromatography and mass spectrometry according to M Rodriguez-Palermo et al 28 at the beginning and at the end of phase 2. The fatty acid composition of the study oils (10 μl sample) was determined by the same method (Table 2).…”