Classification of vegetable oils according to their botanical origin using n-alkane profiles established by GC-MS

Abstract

n-Alkane profiles established by gas chromatography-mass spectrometry (GC-MS) were used to classify vegetable oils according to their botanical origin. The n-alkanes present in corn, grapeseed, hazelnut, olive, peanut and sunflower oils were isolated by means of alkaline hydrolysis followed by silica gel column chromatography of the unsaponifiable fractions. The n-alkane fraction was constituted mainly of n-alkanes in the range C8-C35, although only those most abundant (15 n-alkanes, from 21 to 35 carbon No.) were used as original variables to construct linear discriminant analysis (LDA) models. Ratios of the peak areas selected by pairs were used as predictors. All the oils were correctly classified according to their botanical origin, with assignment probabilities higher than 95%, using an LDA model.

Keywords: Botanical origin; Gas chromatography – mass spectrometry; Linear discriminant analysis; Vegetable oils; n-Alkanes.