Effects of the sniffing port air makeup in gas chromatography-olfactometry

A time-intensity gas chromatography-olfactometry (GCO) apparatus was develo ped to study some aerodynamic parameters that may influence odor detection and intensity measurements by the subjects. The addition of humidified air at the elution place of the compounds is generally recommended for several reasons (essentially to prevent nasal mucosa dehydration and to improve chr omatographic affluent carriage out of the column), but clues about these ef fects are yet to be published. This question is studied through two complem entary experiments using synthetic solutions of 3-methyl-1-butanethiol, hex an-2-one, octanal, nonanal, furfural, citronellal, benzaldehyde, octan-1-ol , 2-phenylethyl acetate, guaiacol, 2-phenylethanol, and vanillin. This work demonstrates the need for an air makeup to increase odor detection frequen cy and intensity rating. With the conditions tested, a minimum makeup air f low rate of 50 L . min(-1) is necessary. On the contrary, humidification of the makeup is useless for the sniffers comfort and to improve the quantita tive GCO results.