scholarly journals Introducing the extended volatility range proton-transfer-reaction mass spectrometer (EVR PTR-MS)

2021 ◽  
Vol 14 (2) ◽  
pp. 1355-1363
Author(s):  
Felix Piel ◽  
Markus Müller ◽  
Klaus Winkler ◽  
Jenny Skytte af Sätra ◽  
Armin Wisthaler
Keyword(s):  
Proton Transfer ◽  
Real Time ◽  
Chemical Ionization ◽  
Transfer Reaction ◽  
Proton Transfer Reaction ◽  
Reaction Mass ◽  
Time Response ◽  
Signal Decay ◽  
Decay Times ◽  
Response Performance

Abstract. Proton-transfer-reaction mass spectrometry (PTR-MS) is widely used in atmospheric sciences for measuring volatile organic compounds in real time. In the most widely used type of PTR-MS instruments, air is directly introduced into a chemical ionization reactor via an inlet capillary system. The reactor has a volumetric exchange time of ∼0.1 s, enabling PTR-MS analyzers to measure at a frequency of 10 Hz. The time response does, however, deteriorate if low-volatility analytes interact with surfaces in the inlet or in the instrument. Herein, we present the extended volatility range (EVR) PTR-MS instrument which mitigates this issue. In the EVR configuration, inlet capillaries are made of passivated stainless steel, and all wetted metal parts in the chemical ionization reactor are surface-passivated with a functionalized hydrogenated amorphous silicon coating. Heating the entire setup (up to 120 ∘C) further improves the time-response performance. We carried out time-response performance tests on a set of 29 analytes having saturation mass concentrations C0 in the range between 10−3 and 105 µg m−3. The 1/e-signal decay times after instant removal of the analyte from the sampling flow were between 0.2 and 90 s for gaseous analytes. We also tested the EVR PTR-MS instrument in combination with the chemical analysis of aerosols online (CHARON) particle inlet, and 1/e-signal decay times were in the range between 5 and 35 s for particulate analytes. We show on a set of example compounds that the time-response performance of the EVR PTR-MS instrument is comparable to that of the fastest flow tube chemical ionization mass spectrometers that are currently in use. The fast time response can be used for rapid (∼1 min equilibration time) switching between gas and particle measurements. The CHARON EVR PTR-MS instrument can thus be used for real-time monitoring of both gaseous and particulate organics in the atmosphere. Finally, we show that the CHARON EVR PTR-MS instrument also rapidly detects highly oxygenated species (with up to eight oxygen atoms) in particles formed by limonene ozonolysis.

scholarly journals Introducing the Extended Volatility Range Proton-Transfer-Reaction Mass Spectrometer (EVR PTR-MS)

2020 ◽  
Author(s):  
Felix Piel ◽  
Markus Müller ◽  
Klaus Winkler ◽  
Jenny Skytte af Sätra ◽  
Armin Wisthaler
Keyword(s):  
Proton Transfer ◽  
Real Time ◽  
Chemical Ionization ◽  
Transfer Reaction ◽  
Proton Transfer Reaction ◽  
Reaction Mass ◽  
Time Response ◽  
Signal Decay ◽  
Decay Times ◽  
Response Performance

Abstract. Proton-transfer-reaction mass spectrometry (PTR-MS) is widely used in atmospheric sciences for measuring volatile organic compounds in real time. In the most widely used type of PTR-MS instruments, air is directly introduced into a chemical ionization reactor via an inlet capillary system. The reactor has a volumetric exchange time of ~ 0.1 s enabling PTR-MS analyzers to measure at a frequency of 10 Hz. The time response does, however, deteriorate if low-volatility analytes interact with surfaces in the inlet or in the instrument. Herein, we present the “Extended Volatility Range” (EVR) PTR-MS instrument which mitigates this issue. In the EVR configuration, inlet capillaries are made of passivated stainless steel and all wetted metal parts in the chemical ionization reactor are surface-passivated with a functionalized hydrogenated amorphous silicon coating. Heating the entire set-up to 120 °C further improves the time-response performance. We carried out time-response performance tests on a set of 29 analytes having saturation mass concentrations C0 in the range between 10−3 and 105 µg m−3. 1/e-signal decay times after instant removal of the analyte from the sampling flow were between 0.2 and 90 s for gaseous analytes. We also tested the EVR PTR-MS instrument in combination with the CHARON particle inlet, and 1/e-signal decay times were in the range between 5 and 35 s for particulate analytes. We show on a set of exemplary compounds that the time-response performance of the EVR PTR-MS instrument is comparable to that of fastest flow tube chemical ionization mass spectrometers that are currently in use. The fast time response can be used for rapid (~ 1 min equilibration time) switching between gas and particle measurements. The CHARON EVR PTR-MS instrument can thus be used for real-time monitoring of both gaseous and particulate organics in the atmosphere. Finally, we show that the CHARON EVR PTR-MS instrument is capable of detecting highly oxygenated species (with up to eight oxygen atoms) in particles formed by limonene ozonolysis.

The applicability of proton transfer reaction-mass spectrometry (PTR-MS) for determination of isocyanic acid (ICA) in work room atmospheres

2014 ◽  
Vol 16 (10) ◽  
pp. 2423-2431 ◽  
Author(s):  
Mikolaj Jan Jankowski ◽  
Raymond Olsen ◽  
Claus Jørgen Nielsen ◽  
Yngvar Thomassen ◽  
Paal Molander
Keyword(s):  
Mass Spectrometry ◽  
Proton Transfer ◽  
Real Time ◽  
Mass Spectrometer ◽  
Transfer Reaction ◽  
Proton Transfer Reaction ◽  
Reaction Mass ◽  
Isocyanic Acid

This study presents a real-time method to quantitatively determine isocyanic acid (ICA) in workroom air using a proton transfer reaction-mass spectrometer (PTR-MS).

scholarly journals A high-resolution time-of-flight chemical ionization mass spectrometer utilizing hydronium ions (H<sub>3</sub>O<sup>+</sup> ToF-CIMS) for measurements of volatile organic compounds in the atmosphere

2016 ◽  
Author(s):  
Bin Yuan ◽  
Abigail Koss ◽  
Carsten Warneke ◽  
Jessica B. Gilman ◽  
Brian M. Lerner ◽  
...  
Keyword(s):  
High Resolution ◽  
Proton Transfer ◽  
Mass Spectrometer ◽  
Chemical Ionization ◽  
Transfer Reaction ◽  
Proton Transfer Reaction ◽  
Reaction Mass ◽  
Ionization Mass ◽  
Hydronium Ions ◽  
Volatile Organic

Abstract. Proton transfer reactions between hydronium ions (H3O+) and volatile organic compounds (VOCs) provide a fast and high sensitive measurement technique for VOCs, leading to extensive use of proton-transfer-reaction mass spectrometry (PTR-MS) in atmospheric research. Based on the same ionization approach, we describe the development of a high-resolution (HR) time of flight chemical ionization mass spectrometer (ToF-CIMS) utilizing H3O+ as the reagent ions. The new H3O+ ToF-CIMS has sensitivities of 100–1000 cps/ppb (ion counts per second per part-per-billion mixing ratio of VOC) and detection limits of 20–600 ppt at 3σ for a 1-second integration time for simultaneous measurements of many VOC species of atmospheric relevance. Compared with similar instruments with quadrupole mass spectrometer, e.g. proton-transfer-reaction mass spectrometers, the ToF analyzer with mass resolution (m/Δm) of up to 6000 not only increases measurement frequency of the instrument, but also expands the number of measurable species. The humidity dependence of the instrument was characterized for various VOC species and the behaviors for different species can be explained by compound-specific properties that affect the ion chemistry. The new H3O+ ToF-CIMS was successfully deployed on the NOAA WP-3D research aircraft for the SONGNEX campaign in spring of 2015. The measured mixing ratios of several aromatics from the H3O+ ToF-CIMS agreed within ±10 % with independent gas chromatography (GC) measurements from whole air samples. Initial results from the SONGNEX measurements demonstrate that the H3O+ ToF-CIMS dataset will be valuable for the identification and characterization of emissions from various sources, investigation of secondary formation of many photochemical organic products and therefore the chemical evolution of gas-phase organic carbon in the atmosphere.

scholarly journals Correction: The stability and generation pattern of thermally formed isocyanic acid (ICA) in air – potential and limitations of proton transfer reaction-mass spectrometry (PTR-MS) for real-time workroom atmosphere measurements

2018 ◽  
Vol 20 (2) ◽  
pp. 416-416
Author(s):  
Mikolaj Jan Jankowski ◽  
Raymond Olsen ◽  
Yngvar Thomassen ◽  
Paal Molander
Keyword(s):  
Mass Spectrometry ◽  
Proton Transfer ◽  
Real Time ◽  
Transfer Reaction ◽  
Proton Transfer Reaction ◽  
Reaction Mass ◽  
Isocyanic Acid ◽  
The Stability

Correction for ‘The stability and generation pattern of thermally formed isocyanic acid (ICA) in air – potential and limitations of proton transfer reaction-mass spectrometry (PTR-MS) for real-time workroom atmosphere measurements’ by Mikolaj Jan Jankowski et al., Environ. Sci.: Processes Impacts, 2016, 18, 810–818.

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