Gas chromatography - Olfactometry (GC-O) purifies odorants and delivers them as 1 to 2 second doses to an olfactometer where their odor properties (quale and intensity) can be studied independent of other odors. Adding an odor to the olfactometer air before combining it with the GC effluent creates an odor pedestal upon which an odorant eluting from the GC can be studied to provide insight into mixture perception. This paper describes the development and testing of a gas chromatography - pedestal olfactometer (GC-PO) that produces a Gaussian shaped distribution of one odorant in a background of constant odor composition (the pedestal). A constant pedestal composition was generated by a dynamic headspace released from poly(ethylene) glycol (PEG) solutions into the humidified air of a gas chromatograph-olfactometer (GCO). A magnetic stirrer kept the solvent at the interface in equilibrium with the remainder of the solution producing a constant (+ 10%) pedestal concentration. The resulting pedestal was then combined with a GC effluent and sent to the sniff port of the GC-O. Hexanal, octanal and decanal were analyzed by gas chromatography-mass spectrometry to test the performance and stability of the pedestal. Volatile concentrations of compounds released in the pedestal of GC-PO were linear, constant and could be turned on and off without any detectable background or residual odo
