Stableflex 24 ga

One (1) g of each type of chocolate was grated in a mortar to form a fine powder. Then, the chocolate powder was added to a septum vial (20 mL). Volatile compounds of each sample were extracted using the Headspace Solid-Phase Microextraction technique (HS-SPME). The fiber used for the extraction was 50/30 µm divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS, Stableflex 24 Ga, Manual Holder) of Supelco. The use of this fiber for cocoa organoleptic analysis allows obtaining a good separation of chromatographic peaks [41 (link)]. The SPME fiber was conditioned in the GC-MS Agilent 7890B’s injector system for 15 min at 250 °C. The conditioning was done below the suggested conditioning temperature provided by Supelco for this fiber type (i.e., 30 min at 270 °C) because it was found that our conditions extended the working life of our fiber without carry over compromise. After fiber conditioning, the SPMEs fibers were exposed to heated chocolate samples (at 60 °C) for 15 min in a thermostat block. Although individuals consume chocolate bars at room temperature, the temperature of 60 °C used was to maximized VOCs emission without risking degradation. The VOCs were then desorbed in the GC-MS Agilent 7890B’s injector system for 10 min at 250 °C.