Detection of Odorant Molecules in the Gaseous Phase Using α-, β-, and γ-Cyclodextrin Films on a Quartz Crystal Microbalance

Abstract

Abstract:There is an interest in sensors for the detection of odorant molecules in the gaseous phase, especially those related to the fragrance of fruits, because odorant sensing is useful for on-site quality control of agricultural products. Previously, gas-chromatographic methods requiring bench-top devices were used for odorant-molecule detection. Herein, we report an odorant sensor based on cyclodextrins (CDs) as a stable odorant receptor, using a highly mass-sensitive and quantitative 27-MHz quartz crystal microbalance (QCM) device, which has the advantage of possible incorporation into portable devices. When ethyl butyrate (a model odorant molecule for fruit fragrances) was flowed onto a QCM plate modified with α-, β-, or γ-CD network films, a decrease in frequency was observed (corresponding to an increase in mass), owing to the capture of odorant molecules by CD molecules. The CD films were capable of capturing and releasing odorant molecules, depending on the type of CD (α-, β-, or γ-CD). Thus, these sensors are reusable for odorant-molecule sensing, and are applicable to pattern recognition of odorant molecules. Thus, sensors based on CD films combined with a QCM handheld device could be applied to monitoring the condition of fruits.

Sensing of Airborne Infochemicals for Green Pest Management: What Is the Challenge?

“…Brezolin et al fabricated gravimetric sensors utilizing silicon cantilevers coated with polyaniline (PANI) or alternating bilayers of multi-wall carbon nanotubes and PANI for the detection of the brown stinkbug ( Euschistus heros ) pheromone, methyl 2,6,10-trimethyl­tridecanoate, with a LOD lower than 1 ppt. , Similarly, Steffens et al used PANI-functionalized cantilevers as sensing elements for the detection and quantification of the alarm pheromone 2-heptanone, with a LOD of 31 ppm . QCM-based sensors have also shown remarkable efficiency in the detection of plant-produced ICs. , Iqbal et al used polystyrene-coated QCM to detect ppm levels (<20 ppm) of limonene, eucalyptol, and α-pinene, which have been applied for the push–pull management of tomato whitefly, Bemisia tabaci , cabbage fly, Delia radicum , and red palm weevil, Rhynchophorus ferrugineus , respectively. − QCM sensors coated with cyclodextrins, cyclic oligosaccharides able to host volatiles in their cavity, were used for the detection of the floral ICs geraniol, ethyl butyrate, and limonene . Additional enhancement of selectivity and sensitivity can be achieved by coating the QCM with MIPs which exhibit tailored recognition sites complementary to targeted volatiles, in terms of shape, size, and functional groups .…”

“…131−134 QCM sensors coated with cyclodextrins, cyclic oligosaccharides able to host volatiles in their cavity, were used for the detection of the floral ICs geraniol, 135 ethyl butyrate, and limonene. 136 Additional enhancement of selectivity and sensitivity can be achieved by coating the QCM with MIPs which exhibit tailored recognition sites complementary to targeted volatiles, in terms of shape, size, and functional groups. 137 Several MIPs-based QCMs were developed to detect various airborne ICs including α-pinene, β-phellandrene, 3-carene, cis-thujopsene, 138 and hexanal.…”