Triacylglycerols analysis is a powerful tool to assess purity of vegetable oils, mainly applied to olive oils. Official methods by EU and IOC standardized RP-HPLC analysis of triacylglycerols to evaluate the amount of ECN42 terms, even if, in many cases, the obtained separation was not satisfactory, the method was adopted to check for extraneous oils with high amounts of oleic acid. An improvement of the method suitable to check for admixtures with several oils had been proposed by substitute acetone/acetonitrile with propionitrile. Ratios between selected TAGs were then calculated. The ECN42 value obtained by using the two different eluting solvents were compared and some discrepancies were highlighted.
Some peculiar mixtures of seed oils and olive oil, however, cannot be detected even by this approaches, while gas chromatography can be a suitable approach.
Capillary GC on short column coated with non polar stationary phase was applied and results suggested that some limits can be proposed for C48 and C60.
Care must be applied to the injection method, as thermal degradation can easily take place.
