Quantitative structure-activity relationships (QSARs) for odor thresholds of volatile organic compounds (VOCs)

A theoretical model for correlating odor thresholds of volatile organic compounds (VOCs) with their simple physicochemical properties has been developed. The partition coefficient between octanol and water, and that between water and air were used to model the partition process of airborne chemicals into the biophase where the olfactory signal is transformed. Validation was performed by fitting data on odor thresholds and partition coefficients for acetates, alcohols, ketones and amines into the model. Quantitative structure-activity relationships (QSARs) for the four series were developed from the model. The results suggest that acetates, alcohols and ketones probably bind to a common receptor site located in the hydrophobic interior of the lipid bi-layer membrane of the olfactory cilia. Amines probably bind to a different receptor site located closer to the mucus layer. The results also suggest that odor thresholds of related VOCs which appear to share a common receptor site may be additive.