Development of a headspace solid phase microextraction- gas chromatography method for monitoring volatile compounds in extended time-course experiments of olive oil.

A novel method for monitoring fibre performance and death, based on a Shewhart control plot, for use in headspace analysis by solid phase microextraction-gas chromatography (SPME-GC) is presented. The method is also demonstrated to be effective in standardising fibre response in extended time'course experiments, where several fibres may be required to complete a lengthy study. Extraction conditions that gave good total recovery and diversity of compounds, from olive oil headspace were found to be: 1 g oil sample in 10 mL vessel; exposure of DVB-CAR-PDMS, 50/30 'm fibre for 30 min at 40 °C; and desorption for 3 min at 250 °C. Calibration curves were constructed for 25 compounds commonly reported in olive oil headspace; with coefficients of determination (R2) ranging from 0.959 to 0.994 and limits of detection (LOD) from 0.01 to 0.59 'g/g. The method was applied to monitor the change in concentration of select C6 volatile compounds, which have implications in sensory quality ' E-2-hexenal, hexanal, E-2-hexen-1-ol, hexanol ' over a period of 12 months storage.