Comparative analysis of oils using different analysis methods

Vegetable oil is a natural product with a high market value, even more so if it is olive oil, but difficult to control quality. Different analysis methods, including Nuclear Magentic Resonance, have been used to find ways to improve this situation. Specially for olive oils, high resolution NMR has been used since 1996 [1-3] for characterization and quality control [4-7]. For this work, different comercially available oils and olive oils were used. Sample preparation for NMR analysis is relatively simple. In this work, 0.4 mL of oil is mixed with 0.2 mL of deuterated solvent, different solvents (DMSO, acetone, chloroform) were used. The smaples used in this work are different edible oils that were found in supermarkets (extra virgin olive oils, corn oils, coconut oil among others). Standard 1H-NMR spectra were acquired and analyzed using metabolomics and chemometric techniques. Because of the observed overlap in the 1H-spectra, 13C-NMR spectra were acquired for further analysis [8]. Analysis of spectra in the methyl region revealed significant differences in both 1H-NMR and 13C-NMR spectra, as well as in the spectra related to palm oil, which showed significant differences that may be related to the presence of polyunsaturated fatty acids [9]. With this we expect a classification of the samples according to the declared quality of the products and the origin [10]. Using the deconvolution method with ML it was possible to identify 2 chemical positions that characterize a categorization of the samples demonstrated so far. All techniques are well established, and have been used regularly in the laboratory for years

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