A versatile and compact reference gas generator for calibration of ion mobility spectrometers
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TECHNICAL REPORT
A versatile and compact reference gas generator for calibration of ion mobility spectrometers Thomas Mayer 1
&
Malcolm Cämmerer 1 & Helko Borsdorf 1
Received: 20 May 2019 / Revised: 6 June 2019 / Accepted: 9 June 2019 # Springer-Verlag GmbH Germany, part of Springer Nature 2019
Abstract We developed a versatile and compact reference gas generator for the calibration of ion mobility spectrometers or other gas detection technologies. The principle is based on the use of permeation tubes or diffusion vessels. This approach allows the reference gas to be generated with very low concentrations of analytes. In contrast to most of the commercially available instruments, which dilute the complete permeation gas stream, we only used an aliquot for further dilution and the necessary quantity of inert gas can be considerably reduced. The permeation cell can be operated at elevated or reduced temperatures relative to ambient temperature. This temperature control allows the permeation rate to be adjusted depending on the volatility of the investigated substance and the membrane material used in the permeation tubes. As all connection lines and the mixing chamber after the permeation chamber are held at 70 °C, memory effects can be minimized. As a result, stable permeation rates can be rapidly achieved and the regeneration period after removing the substances from the permeation vessel significantly reduced. In this study, the analytical performance of the reference gas generator was validated using DMMP due to its importance for ion mobility measurements. Keywords Reference gas generator . Permeation tubes . Ion mobility spectrometry
Introduction Very volatile organic compounds (VVOCs; boiling points below 100 °C), volatile organic compounds (VOCs; boiling points between 100 °C and 240/260 °C) and semi volatile organic compounds (SVOC; boiling points between 240/ 260 °C and 400 °C) [1] are routinely measured as they are major components of indoor and outdoor air pollution [2]. Furthermore, these compounds include warfare agents, explosives [3], industrial products and by-products and biological metabolites (e.g. exhaled breath analysis). The ability to generate defined trace gas concentrations is therefore a prerequisite for the calibration or validation of analytical devices and the investigation of gas phase reactions. There are different approaches for the dynamic generation of reference gases. In contrast to static methods, where the target substances are * Thomas Mayer [email protected] 1
UFZ-Helmholtz Centre for Environmental Research, Department Monitoring and Exploration Technologies, Permoserstraße 15, D-04318 Leipzig, Germany
injected in a defined volume of inert gas at a known pressure, dynamic methods permit the continuous generation of reference gases with variable concentrations. Permeation methods, diffusion methods, the continuous injection of substance with a syringe pump, evaporation methods, electrolytic methods or chemical methods are commonly used for the dynamic generation of ref
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