Odorant detection capability of QCR sensors coated with plasma deposited organic films

Odorant-detection experiments were conducted on major single-odor substance s in various types of botanical species. The sensing devices we used were q uartz-crystal resonators (QCRs), radio-frequency (RF) sputtered with amino acids or polymers. The odorants were generated at very low concentrations ( ppb level) by using the diffusion-tube method. The tested odorants were det ected at concentrations between 0.3 and 940 ppb. These deposited films had high partition coefficients for the odorants, confirming their high sensiti vity to organic vapors, especially to terpenoids. This indicates that the o dorant solvation is due to odorant-film interaction related to Gibbs free e nergy. (C) 1999 Elsevier Science S.A. All rights reserved.