Evaluation of Fatty Acids Composition of Some Food Samples by Using GC-MS and NMR Techniques

Abstract

Abstract The purpose of this paper was to compare the composition (weight % of total identified FA) in saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids from 3 food matrices (sunflower oil, palm oil and lard) by 2 different techniques, gas chromatography - mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR). For GC-MS technique, fatty acid methyl esters (FAMEs) identification in the samples was performed by comparison of the retention times (RT) and the mass/charge (m/z) ratio characteristic of each FAME component in the reference standards used (F.A.M.E. Mix C4 - C24 and SRM®2377). FAMEs quantification from food samples was realized by applying correction factors calculated based on reference standards. NMR spectra were recorded on a Bruker Advance 400 MHz spectrometer, operating at 9.4 Tesla corresponding to the resonance frequency of 400.13 MHz for the 1H nucleus. The NMR spectra was recorded directly on the oil without any sample preparation. The difference between the mean values of the fatty acids content determined by GC-MS and NMR was not more than ± 15% for sunflower oil and lard, and ± 6% for palm oil.