The ultra-low detection limits of the Vocus PTR-TOF mass spectrometer permit the monitoring of sub-second transformations in human breath VOC emissions, ranging from ppt to ppm concentration.
Luca Cappellin and Felipe Lopez
TOFWERK, Thun, Switzerland
Researchers across multiple disciplines are regularly required to characterize the emission and evolution of target volatile organic compounds (VOCs) during rapid biological, chemical or industrial processes.
Proton Transfer Reaction Mass Spectrometry for the Identification of VOCs
Measuring these properties necessitates online monitoring methodologies with large dynamic range and high time resolution. Proton Transfer Reaction Mass Spectrometry (PTR-MS) represents an ultra-sensitive technique for the real-time identification of various VOCs.
The Vocus PTR-TOF is capable of concurrently measuring substantial quantities of VOCs with ultra-low detection limits, high mass resolving power and rapid time response. To exhibit its capacity to observe dynamic transformations in a composite VOC mixture, direct measurements of human breath were taken during the consumption of a RicolaTM herb cough drop.
Each of the 13 herbs in these cough drops possesses its own aroma compounds at concentrations spanning multiple orders of magnitude.
The figure below indicates the evolution of select VOCs throughout the ingestion of the cough drop. High resolution PTR-MS information was saved at a rate of 3 mass spectra/sec, allowing the capturing of fast VOC transformations relating to herb aroma and metabolism.
1 pptv fluctuations of menthyl acetate were captured at sub-second resolution. At the same time, the instrument captured fast transformation in C10H16 monoterpenes, which manifested concentrations of 5 to 6 orders of magnitude greater than menthyl acetate.
Real-time monitoring of VOCs in human breath throughout the consumption of a RicolaTM herb cough drop. Human breath was directly sampled into the inlet of a Vocus PTR-TOF 2R before and after ingestion of the cough drop. High-resolution data were saved at a rate of 3 mass spectra/sec to capture rapid and large-magnitude changes in both herb aroma VOCs, such.as terpenes and esters, and VOCs related to the human metabolism, such as isoprene, with sub-second resolution. Concentrations of the monitored species spanned more than 6 orders of magnitude during the experiment (ppt to ppm).
This information has been sourced, reviewed and adapted from materials provided by TOFWERK.
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