Junichi Ide

Discrimination of aromatic optical isomers using quartz-resonator sensors

Abstract In the present study, the discrimination of optical isomers with closely similar aromas has been performed using quartz-resonator gas sensors. It has been found that the difference between the sensor outputs of a dextrorotatory optical isomer ( d -isomer) and of a laevorotatory one ( l -isomer) is negligibly small when phospholipid films, gas-chromatographic stationary-phase materials and cellulosic films are used for the coating-film materials on quartz-resonator gas sensors. In contrast, when a typical chiral compound such as cyclodextrin is used as the film material, the optical isomers can be successfully discriminated.

Development of odour-sensing system using an auto-sampling stage

Abstract The present authors previously reported that odours could be discriminated by a sensing system using a quartz-resonator sensor array and neutral-network pattern recognition. In that system, however, the number of samples was limited due to the increase in the number of solenoid valves. A new system for measuring many samples has been developed recently, in which two syringe needles driven by a XYZ mechanical stage are inserted into a vial with a rubber stopper where a sample is poured. A dry air supply through needles carries odourant vapour to a sensor array. This sequence continues repeatedly to measure many samples automatically. By modifying experimental parameters, the mean coefficient of variation can be suppressed to 3.3%. 80 data for 20 typical essential oils have been measured in 320 min by the present system.

Record of mint flavor using mass spectrometry

Although GC/MS is a standard technique to analyze gases, a combination of mass spectrometry with a pattern recognition technique enables us to evaluate smells rapidly because lengthy measurement of gas chromatography is eliminated. Although several researchers have reported the classification of smells only using mass spectrometry, the estimation of the sensory-test result has not been studied. A neural network enables us to map the mass spectrum into the human sensory space. In this study, mint flavors were focused on. Four spearmint flavors and their mixtures were successfully separated and quantified only using the mass spectrum. Then, the mixtures of those flavors and peppermint flavor were evaluated. The scores of the sensory test such as QDA (quantitative descriptive analysis) method were estimated using the mass spectrometry and SOM (self-organized map). It was found that the accuracy of the estimated value using the SOM was better than that obtained according to the linear superposition theorem

Development of Odor-Sensing System Using an Auto-Sampling Stage and Identification of Natural Essential Oils

An odor-sensing system is desirable for use in a broad variety of fields, from the food, drink, and cosmetics industries, to use in environmental and other protection fields. The human sensory tests now utilized to discriminate odors in those fields are inevitably affected by the inspector’s state of health and mood. It is therefore essential that an objective evaluation method be developed for practical use.