Carbograph 5dt

VOC sample collection involved placing a stainless steel hood over each of the carcasses or control site and allowing the headspace to accumulate for 15 min [20] . The headspace was sampled dynamically by attaching an ACTI-VOC low flow air sampling pump (Markes international Ltd., Llantrisant, UK) to one end of a sorbent tube containing Tenax TA and Carbograph 5DT (Markes International Ltd.) and attaching the other end of the sorbent tube to a sampling port on the stainless steel hood (see [20] for a schematic). Air was pumped into the sorbent tube at a flow rate of 100 mL/min for 10 min to obtain a 1 L sample of the headspace above the pig carcass or control site. In accordance with the EPA Method (TO-17)[38] , all tubes were sealed with brass storage-caps, wrapped in aluminium foil and placed in a glass air-tight container for transportation to the laboratory. A field blank sample was collected on each experimental day prior to the first sample collection to account for natural variation in the atmospheric VOC profile. Field blanks were collected by uncapping a blank tube for 30 s at the field site and then re-capping the tube as documented in previous studies [22 , 23 (link), 30 , 39 ]. The field blank tubes were stored with the experimental sorbent tubes to account for contamination or artefacts that may have resulted during the storage period.

Volatilomes
were collected through optimized methods as described in Brown et
al.^{40 (link)} using preconditioned dual sorbent
tubes (Tenax and Carbograph 5DT Markes International Ltd., UK; parts
number C2-AAXX-5149).