Detection and evaluation of fragrances by human reactions using a chemical sensor based on adsorbate detection.

Human reactions and sensor responses to 37 typical fragrances are investigated in order to develop a chemical sensor which can detect fragrances and evaluate them in subjective terms of human reactions. Eight female test subjects recorded their reactions to these fragrances by grading them on a seven-point scale in terms of 55 descriptive characteristics. Their reactions fell into two general categories, "pleasantness" and "freshness (elegance)", dependent on the characteristic chemical structure of the fragrances. The women evaluate the fragrances mainly by the degree of pleasantness and freshness (elegance). A set of eight plezoelectric sensors incorporating different hydrophobic polymer materials is fabricated to predict such human reactions because their adsorbate detection and pattern recognition are similar to those in humans. The sensors were effective in detecting hydrophobic fragrances in the gas phase, and their fragrance classifications were similar to human ones. The sensor responses to the adsorbate correlate significantly with two of the human responses with multiple correlation coefficients of more than 0.6 (p < 0.02). Namely, the sensor can predict two different human reactions to fragrances simultaneously, suggesting the possibility of developing an artificial olfactory sensor based on adsorbate detection.