Rapid Recognition of Olive Oil Adulterated with Hazelnut Oil by Direct Analysis of the Enantiomeric Composition of Filbertone

On-line coupling of reversed-phase liquid chromatography to gas chromatography (RPLC-GC) using a programmable temperature vaporizer (PTV) as an interface is used for detecting adulterations of hazelnut oil in olive oil on the basis of the determination of the enantiomeric composition of ( E )-5-methylhept-2-en-4-one (filbertone). Different variables (i.e., packing material used for trapping the LC−GC transferred solutes, desorption temperature, and eluent composition of the mobile phase during the LC preseparation) are investigated in terms of their influence on the sensitivity achievable in the RPLC-GC analysis. The method does not require any type of sample pretreatment, thus allowing the direct and rapid analysis (under 50 min) of sample oils. Working under the experimental conditions proposed, adulterations of olive oils with hazelnut oil percentages lower than 5% are detectable.