page_title: Proton-transfer-reaction mass spectrometry
section_title: Food science
hierarchical_section_title: Proton-transfer-reaction mass spectrometry / Applications / Food science
caption_attribution_description: English: PTR-MS measurement (HS PTR-MS; IONICON Analytik, AUSTRIA) of person's breath after sipping a drink containing vanillin
context_page_description: Proton-transfer-reaction mass spectrometry is an analytical chemistry technique that uses gas phase hydronium reagent ions which are produced in an ion source. PTR-MS is used for online monitoring of volatile organic compounds in ambient air and was developed in 1995 by scientists at the Institut für Ionenphysik at the Leopold-Franzens University in Innsbruck, Austria.
  A PTR-MS instrument consists of an ion source that is directly connected to a drift tube and an analyzing system. Commercially available PTR-MS instruments have a response time of about 100 ms and reach a detection limit in the single digit pptv or even ppqv region. Established fields of application are environmental research, food and flavor science, biological research, medicine, Homeland security, cleanroom monitoring, etc.
context_section_description: Fig. 2 shows a typical PTR-MS measurement performed in food and flavor research. The test person swallows a sip of a vanillin flavored drink and breathes via his nose into a heated inlet device coupled to a PTR-MS instrument. Due to the high time resolution and sensitivity of the instrument used here, the development of vanillin in the person's breath can be monitored in real-time (please note that isoprene is shown in this figure because it is a product of human metabolism and therefore acts as an indicator for the breath cycles). The data can be used for food design, i.e. for adjusting the intensity and duration of vanillin flavor tasted by the consumer.
  Another example for the application of PTR-MS in food science was published in 2008 by C. Lindinger et al. in Analytical Chemistry. This publication found great response even in non-scientific media. Lindinger et al. developed a method to convert "dry" data from a PTR-MS instrument that measured headspace air from different coffee samples into expressions of flavor (e.g. "woody", "winey", "flowery", etc.) and showed that the obtained flavor profiles matched nicely to the ones created by a panel of European coffee tasting experts.
caption: Fig. 2: PTR-MS measurement of vanillin dissemination in human breath. Isoprene is a product of human metabolism and acts as an indicator for breath cycles. (The measurement was performed utilizing a "N.A.S.E."[41] inlet system coupled to a "HS PTR-MS".)
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