On‐line LC‐GC method for determination of isomers of nervonic acid in meat‐derived food

Abstract

AbstractAn on‐line liquid chromatography‐gas chromatography (LC‐GC) method for determination of the cis/trans isomers of nervonic acid in meat‐derived food is described. The technique used a home‐assembled LC‐GC coupled system. A simple LC clean‐up procedure using an analytical gel permeation (5 μm) column and 1% ethyl acetate in hexane as mobile phase has proved to be suitable for the isolation and purification of fatty acid methyl esters from the meat matrix. Use of a silica gel (5 μm) pre‐column improved the separation of cis/trans nervonic acid from cholesterol and the more polar constituents of the extracted fraction. GC analyses were performed using a non‐polar GC column and mass spectrometry (MS) for identification of the analytes and flame ionization detector (FID) for quantification of the compounds studied. Excellent linearity with correlation coefficients higher than 0.999 in the range of 0.05–10 μg mL–1 nervonic acid and a good repeatability with relative standard deviation (RSD) values generally lower than 4% was obtained. The method developed provides a high sensitivity for trace analysis of the cis/trans isomers of nervonic acid and enables complete automation.