Analysis of Volatile Hydrocarbons (Pentene Dimers
and Terpenes) in Extra Virgin Olive Oil: Optimization by Response
Surface Methodology and Validation of HS-SPME-GC-MS Method
A head
space-solid phase microextraction-gas chromatography–mass
spectrometery (HS-SPME-GC-MS) method for the simultaneous analysis
of pentene dimers from lipoxygenase (LOX) pathway, monoterpenes, and
sesquiterpenes in extra virgin olive oil (EVOO) was proposed. A Doehlert
design was performed; the conditions of the HS-SPME preconcentration
step (extraction temperature, extraction time, sample amount, and
desorption time) were optimized by response surface methodology, allowing
defining the method operable design region. A quantitative method
was set up using the multiple internal standard normalization approach:
four internal standards were used, and the most suitable one was selected
for area normalization of each external standard. The quantitative
method was successfully validated and applied to a series of monocultivar
EVOOs. This is the first paper in which a quantitative method using
commercial standards has been proposed for the analysis of an important
class of molecules of EVOO such as pentene dimers. The optimized method
is suitable for routine analysis aimed at characterizing high quality
EVOOs.