Monitoring Trace VOCs in the Atmosphere with PTR-TOF

PTR-MS is the benchmark technique for rapid, quantitative and ultra-sensitive analysis of nearly the whole range of atmospheric organics. This method is used in an extensive range of applications in environmental studies.

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Introduction

• Rugged and consistent technology for sampling volatile organic compounds in the atmosphere at ultra-low trace levels (lower than or equal to single-digit pptV).
• PTR-TOFMS enables both targeted (for example, aromatic species monitoring) and untargeted analyses (for example, oxidation products analysis) of users’ samples on a molecular composition level.
• H₃O⁺ primary reagent ions quantitatively ionize nearly the whole range of atmospheric non-methane organics.
• Even the stickiest compounds (for example, highly oxidized compounds or PAHs) can be examined with IONICON’s EVR option. 
• Users can expand the capability of their PTR-TOFMS from the gas phase to the particle phase using the genuine CHARON particle inlet from IONICON.
• Supplementary acquisition modes improve the selectivity of users’ measurements, which involve the isolation of isomers by the FastGC method, or the use of alternative reagent ions, such as NH₄⁺ and NO⁺.

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Applications

Emission Studies

Emission analyses potentially reflect one of the widest ranges of applications for PTR-MS. A common feature in these analyses is that they usually need a high dynamic range to detect VOCs from sub-pptV concentrations of up to ppmV levels. This range is easily covered by PTR-MS. Standard emission studies are as follows:

• Urban emissions: Müller et al., 2017
• Biomass burning emissions: Stockwell et al., 2015
• Marine emissions: Sanchez et al., 2018
• Biogenic emissions: Ruuskanen et al., 2011
• Agricultural emissions: Sun et al., 2015
• Oil and gas emissions: Halliday et al., 2013

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Reaction Kinetics Studies

PTR-MS is the perfect analytical equipment to comprehend the reaction kinetics that takes place in the air. Through the H₃O⁺ mode, the rise of primary products and the photochemical decay of parent molecules can be quantitatively tracked.

The NH₄⁺ mode is even softer and perfect for characterizing more oxidized products, such as peroxides and esters. Reaction kinetics analyses include the following:

• Directly in the atmosphere: Müller et al., 2016
• Laboratory experiments: Müller et al., 2012

Measurements on Mobile Platforms

PTR-MS is a highly rugged technology that could be deployed in or on mobile platforms. Users can take a look at the specialized mobile VOC monitor PTR-TOF QB or contact IONICON for tailored mobile solutions. Potential platforms are as follows:

• Aircrafts: Chen et al., 2019
• Ships: Tjernström et al., 2013
• Mobile labs and measurement vans: Zemek et al., 2019

This information has been sourced, reviewed and adapted from materials provided by IONICON Analytik.

For more information on this source, please visit IONICON Analytik.