Chemosensory detectability of 1-butanol and 2-heptanone singly and in binary mixtures.

Using 1-butanol and 2-heptanone as stimuli, we measured detectability (i.e., psychometric) functions for the odor, nasal pungency, and eye irritation of these two substances alone and in binary mixtures. Nasal pungency responses were tested in subjects lacking olfaction (i.e., anosmics) for whom odors do not interfere. Eye irritation responses were tested in normosmics and anosmics, and found to be similar in both groups so their results were pooled. When all stimuli--single and mixtures--were transformed into concentration units of one (or the other) chemical, a single function could fit all data from the same sensory end point with a correlation coefficient of 0.91 or higher. The outcome lends support, as a first approximation, to the notion of chemosensory agonism, in the sense of dose additivity, between the members of binary mixtures presented at perithreshold levels.