A quick discrimination of vegetable oil by solid-phase microextraction method

Abstract 

A trace amount of vegetable oil was picked up with solid-phase microextraction (SPME) fiber and identified using a gas chromatograph–mass spectrometer (GC–MS). Unsaponifiable constituents such as sterols could be detected by an injection of the SPME fiber, with the fiber touching the vegetable oil and then leading directly into the port of the GC–MS. After thermal desorption of unsaponifiable constituents, the remaining triacylglycerols or oil that was freshly added to the fiber were recovered with a little organic solvent, and the profiles of the fatty acids that had been constructing the acylglycerols were determined using a base-catalyzed trans-esterification method which produced fatty acid methyl esters. The simple and rapid techniques that make up this method make it possible to significantly reduce the preparation time and as well as the required sample volume. When urgent discrimination is required with high accuracy, this technique could serve as a useful and powerful tool for identification of vegetable oil.

Keywords: Solid-phase microextraction, Vegetable oil, Lipid, Sterol, Gas chromatography, Mass spectrometry