Discrimination of vegetable oils by triacylglycerols evaluation of profile using HPLC/ELSD

This paper describes an HPLC procedure for the determination of triacylglycerol (TAG) profile in vegetable oils. Sample preparation consisted in the dissolution of the oils in acetone and filtration. The chromatographic separation was achieved using a Kromasil 100 C-18 column (at 25 degrees C and gradient elution with acetone and acetonitrile. Elution was performed at a solvent flow rate of 1 mL/min. Detection was accomplished with an evaporative light scattering detector (ELSD), with the following settings: evaporator temperature 40 degrees C, air pressure 3.5 bars and photomultiplier sensitivity 6. TAG peaks were identified taking into account the logarithms of a in relation to homogeneous TAG (relative retention times to triolein) and their quantification was based on the internal normalization method. The linearity, precision and relative response of the method were examined. A total of 15 peaks were separated, identified, and quantified based on the relative percentage peak area. After validation the methodology was applied to eight vegetable oils including olive oil in a total of 52 samples. The proposed method appears to be an adequate method for quality control and a useful tool for authenticity issues. (c) 2005 Elsevier Ltd. All rights reserved.