3.2.3. Static volatile collection
Static odour sampling can be carried out using several sampling techniques. The use of SPME fibres is the most convenient in a closed head space environment (see section 18.104.22.168.1). For this procedure:
8. Gently disconnect the air supply and vacuum pumps from the odour containment glass jars after purging for 15-20 min.
9. Immediately close all ports with screw caps lined with flexible Teflon linings.
10. Insert a SPME fibre holder or gas tight syringe by pushing its needle through one of the flexible Teflon linings of the screw caps until the needle is fully within the glass jar.
11a. Expose the fibre (adsorbent) through the needle tip by pushing down the SPME holder plunger. Maintain this experimental setup for 0.5 - 12 h (or for a desired duration which should not be lengthy to avoid stressing the bees).
11b. For the gas tight syringe, maintain a closed experimental setup for 0.5 - 12 h and afterwards sample the head space odour by pulling a desired volume of air from the head space and analyse directly on a GC, coupled GC-EAD or GC-MS (see section 2.2.4.).
12. Retract the SPME fibre into the needle before withdrawing the needle from the Teflon lining.
13. Analyse sample as described in the previous section (see section 2.2.3. on in situ volatile collection and analysis)