Journal of Japan Association on Odor Environment
Online ISSN : 1349-7847
Print ISSN : 1348-2904
Volume 45 , Issue 1
Showing 1-7 articles out of 7 articles from the selected issue
Special Issue (Current Topics of Instrumental Analysis)
Research paper
  • Koichiro IWAI, Kazumi HAYAKAWA, Hiroshi ITO, Hajime OHTANI
    2014 Volume 45 Issue 1 Pages 29-37
    Published: January 25, 2014
    Released: February 13, 2018

    Thermal desorption-gas chromatography-mass spectrometry/olfactometry (TD-GC-MS/O) is a useful method to specify odor compounds in the complex odor. However, a number of odor compounds are chemically unstable, odor quality often changes by thermal decomposition and/or oxidation of the odor compounds in multistep analytical procedures. In this work, to minimize the change in odor quality, 3 steps of test methods were examined; Test 1: Determination of the most appropriate temperature at the thermal desorption process, Test 2: Confirmation of optimal analytical conditions of TD-GC-MS/O, and Test 3: Verification of the detected odors in TD-GC-MS/O analysis. To achieve these test methods, the specific odor of new Tenax TA porous polymer beads produced by heating at 280°C(Tenax TA odor) was used along with Carbotrap300 adsorbent. Both the most appropriate temperature at the thermal desorption process and the maximum temperature in the instrument were estimated to be 250°C by Test 1 and 2. Under the optimized conditions, twelve element odor compounds in Tenax TA odor were specified by three panels using TD-GC-MS/O, among which seven odor compounds were identified by mass spectrum. These results demonstrated that the 3 steps of the proposed test methods were suitable for the optimization of TD-GC-MS/O analytical conditions.

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  • Tomoko MATSUBASA, Naomi GOTOW, Yasushiro GOMI, Tatsu KOBAYAKAWA
    2014 Volume 45 Issue 1 Pages 38-45
    Published: January 25, 2014
    Released: February 13, 2018

    Among researchers of human olfaction, there is no consensus definition of adaptation yet, because few studies have clearly defined the time-course transition of perceived intensity regarded as adaptation. In order to address this situation, we defined adaptation as a situation in which perceived intensity decreases exponentially with the passage of time. In this study, we performed real-time evaluation of perceived intensity of continuously presented odors, using nine odorants. In order to develop a quantitative method for classifying perceived-intensity curves as ‘adaptation’ or ‘non-adaptation’, each perceived-intensity curve was approximated by an exponential model. We classified perceived-intensity curves as ‘adaptation’, if they fulfilled the following two criteria : (1) theoretical values of perceived intensity correlated strongly with measured values of perceived intensity, and (2) theoretical values of perceived intensity decreased below the detection threshold during odor presentation. Furthermore, we calculated the ratio of the numbers of ‘adaptation’ and ‘non-adaptation’ perceived-intensity curves, for each odor. We called this value the ‘adaptation index’, and proposed it as a quantitative index of the facility with which adaptation to each continuously presented odor occurs.

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