A Method for Controlled Odor Delivery in Olfactory Field-Testing

A widely recognized limitation in mammalian olfactory research is the lack of current methods for measuring odor availability (i.e., the quantifiable amount of odor presented and thus available for olfaction) of training or testing materials during behavioral or operational testing. This research utilized an existing technology known as Controlled Odor Mimic Permeation Systems (COMPS) to produce a reproducible, field-appropriate odor delivery method that can be analytically validated and quantified, akin to laboratory-based research methods, such as permeation devices that deliver a stable concentration of a specific chemical vapor for instrumental testing purposes. COMPS were created for 12 compounds across a range of carbon chain lengths and functional groups in such a way to produce similar permeation rates for all compounds. Using detection canines as a model, field-testing was performed to assess the efficacy of the method. Additionally headspace concentrations over time were measured as confirmation of odor availability using either externally sampled internal standard-solid phase microextraction-gas chromatography-mass spectrometry (ESIS-SPME-GC-MS) or collection onto a programmable temperature vaporizing (PTV) GC inlet with MS detection. Finally, lifetime usage was considered. An efficient method for producing and measuring reliable odor availabilities across various chemical functional groups was developed, addressing a noted gap in existing literature that will advance canine and other nonhuman mammal research testing.