Determination of the Enantiomeric Composition of γ-Lactones in Edible Oils by On-Line Coupled High Performance Liquid Chromatography and Gas Chromatography

A new method is proposed for the determination of the enantiomeric composition of γ-lactones in different vegetable edible oils (i.e., olive oil, almond oil, hazelnut oil, peanut oil, and walnut oil), and its potential for authenticity control is underlined for a limited number of samples. The method is based on the direct injection (i.e., without requiring a sample pretreatment step) in on-line coupled reversed phase liquid chromatography to gas chromatography (RPLC-GC) using a chiral stationary phase in the GC-step. Different experimental values for both speed of sample introduction into GC and volume of the transferred fraction are considered to improve the recoveries obtained. Relative standard deviations lower than 10% and detection limits ranging from 0.06 to 0.22 mg/L were achieved for the investigated γ-lactones. Keywords: Enantiomeric composition; lactones; edible oils; on-line RPLC-GC