Quartz Crystal Microbalance Odor Research Articles

水晶振動子式ニオイセンサシステムの機能設計と開発に関するレビュー

Functional design of organic polymer thin films as the molecular recognition membrane of quartz crystal microbalance (QCM)-type odor sensor system is reviewed. The organic polymer materials which are used as the molecular recognition membrane of QCM odor sensors are selected in the view of solubility parameters. It is found that the solubility parameter is very useful to choice the organic polymers as the molecular recognition membrane of the QCM gas sensors for target gas and odor. It is also found that the use of polymer films with nano-wires is effective to increase the sensitivity of the QCM odor sensors.

Highly sensitive QCM odor sensors with lipopolymeric nanocomposites and physisorbed amphiphilic GC materials

Purpose – This work has been motivated by the authors' long‐term research on odor‐sensing systems using acoustic wave‐based sensors and pattern recognition techniques. The sensors should be fabricated in such a way that they mimic performance of the olfactory receptors. In these terms, the purpose of this paper is to test a simple method for fabrication of quartz crystal microbalance (QCM) sensors by using nanocomposites and amphiphilic gas chromatography (GC) materials. The obtained sensors were intended to be highly sensitive to odorants at low concentrations and in high‐humidity conditions, as well as contributing to discrimination among odorant samples.

Chemisorbed PEGylated lipopolymers as sensing film supports for QCM odor sensors

We report application of the PEGylated lipids (PEG lipopolymers) containing disulphide as supports for sensing films for quartz crystal microbalance (QCM) odor sensors. The materials are binding covalently to the surface of gold QCM sensor electrode creating self-assembled cushion. Additional amounts of lipid or lipid-derived materials can be physisorbed on that chemisorbed coating. Both processes do not require much labor and can be performed with minimum instruments in a simple process. The sensors fabricated with the chemisorbed supports are more sensitive to the tested odorants than their non-supported counterparts. Enhanced sensitivity is derived from higher fluidity of the supported films in comparison to the non-supported ones. Discrimination capability among odorants is also better for the sensors with chemisorbed supports than for the non-supported ones—there are no overlaps between the sample groups and the samples are clustered closely within the groups. Overall, the studied supported sensors introduce interesting properties that can be utilized in the odor sensing systems using QCM sensors.

Study of PEG Tether Length of Pegylated-Lipid Sensing Films in QCM Odor Sensors

Odor sensing system using quartz crystal microbalance (QCM) sensor array and pattern recognition technique has been for a long time an important research topic. Research of novel sensing materials for QCM odor sensors is vital for realization of artificial olfaction and related devices such as odor recorder. Herein we study quartz crystal microbalance (QCM, 20 MHz, AT-cut) sensors coated with lipopolymers with polyethylene glycol (PEG) as a tether. The tether's molecular weights were 1000, 2000 and 5000. In addition, we fabricated QCM sensors coated with PEGs of molecular weights 1000, 2000 and 4000. The fabricated sensors' properties were evaluated during experiments of exposures to vapors of alcohols, esters and acids. From the obtained results it is clear that the tether's length (molecular weight) is an important factor influencing the resulting material's sensing properties. Sensititivity patterns of the lipopolymeric sensors were clealrly different from the ones for respective polymers. The obtained sensors seem to have a good capability to discriminate among odor samples according to the functional group of an odorant.

Odor approximation of fruit flavors using a QCM odor sensing system

Odor approximations of orange and melon flavors were performed using an array of quartz crystal microbalance (QCM) odor sensors coated with different materials, such as lipids and stationary phase materials of gas chromatography (GC). The steady state sensor responses to single flavor components were measured and the data were used to estimate the important odor components by means of a computational two-level quantization method. From these results, the experimental approximations using the steady state sensor responses and principal component analysis (PCA) were performed. In both cases, orange and melon flavors, it was possible to approximate the recipes with only three odor components. Moreover, the similarities between the approximated odors and the original ones were evaluated by a human sensory test. It was found that these similarities were high, especially in the case of orange flavor.