A membrane introduction mass spectrometer utilizing ion-molecule reactions for the on-line speciation and quantitation of volatile organic molecules

2015 ◽  
Vol 29 (23) ◽  
pp. 2187-2194 ◽  
Author(s):  
Nicholas G. Davey ◽  
Ryan J. Bell ◽  
Erik T. Krogh ◽  
Chris G. Gill
Keyword(s):  
Mass Spectrometer ◽  
Organic Molecules ◽  
Ion Molecule Reactions ◽  
Volatile Organic ◽  
On Line

scholarly journals Aqueous phase processing of secondary organic aerosols

2011 ◽  
Vol 11 (7) ◽  
pp. 21489-21532 ◽  
Author(s):  
◽  
T. Tritscher ◽  
A. P. Praplan ◽  
P. F. DeCarlo ◽  
B. Temime-Roussel ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Aqueous Phase ◽  
Mass Spectrometer ◽  
Atmospheric Pressure ◽  
Smog Chamber ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Volatile Organic ◽  
On Line ◽  
Physical And Chemical

Abstract. The aging of secondary organic aerosol (SOA) by photooxidation in the aqueous phase was experimentally investigated. To simulate multiphase processes, the following experiments were sequentially performed in a smog chamber and in an aqueous phase photoreactor: (1) Gas-phase photooxidation of three different volatile organic compounds (VOC): isoprene, α-pinene, and 1,3,5-trimethylbenzene (TMB) in the presence of NOx, leading to the formation of SOA which was subjected to on-line physical and chemical analysis; (2) particle-to-liquid transfer of water soluble species of SOA using filter sampling and aqueous extraction; (3) aqueous-phase photooxidation of the obtained water extracts; and (4) nebulization of the solutions for a repetition of the on-line characterization. SOA concentrations in the chamber measured with a scanning mobility particle sizer (SMPS) were higher than 200 μg m−3, as the experiments were conducted under high initial concentrations of volatile organic compounds (VOC) and NOx. The aging of SOA through aqueous phase processing was investigated by measuring the physical and chemical properties of the particles online before and after processing using a high resolution time-of-flight aerosol mass spectrometer (AMS) and a hygroscopicity tandem differential mobility analyzer (H-TDMA). It was shown that, after aqueous phase processing, the particles were significantly more hygroscopic, and contained more fragmentation ions at m/z = 44 and less ions at m/z = 43, thus showing a significant impact on SOA aging for the three different precursors. Additionally, the particles were analyzed with a thermal desorption atmospheric pressure ionization aerosol mass spectrometer (TD-API-AMS). Comparing the smog chamber SOA composition and non processed nebulized aqueous extracts with this technique revealed that sampling, extraction and/or nebulization did not significantly impact the chemical composition of SOA formed from isoprene and α-pinene, whereas it affected that formed from TMB. For the two first precursors, the aqueous phase chemical composition of SOA was further investigated using offline measurements, i.e. ion chromatography coupled to a mass spectrometer (IC-MS) and an atmospheric pressure chemical ionization mass spectrometer (APCI-MS) equipped with high pressure liquid chromatography (HPLC-MS). These analyses showed that aqueous phase processing enhanced the formation of some compounds already present in the SOA, thus confirming the aging effect of aqueous phase processes. For isoprene experiments, additional new compounds, likely oligomers, were formed through aqueous phase photooxidation, and their possible origins are discussed.

scholarly journals Measurement report: Molecular composition and volatility of gaseous organic compounds in a boreal forest: from volatile organic compounds to highly oxygenated organic molecules

2020 ◽  
Author(s):  
Wei Huang ◽  
Haiyan Li ◽  
Nina Sarnela ◽  
Liine Heikkinen ◽  
Yee Jun Tham ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Boreal Forest ◽  
Organic Compounds ◽  
Mass Spectrometer ◽  
Organic Molecules ◽  
Measurement Techniques ◽  
Time Of Flight ◽  
Molecular Composition ◽  
Flight Mass Spectrometer ◽  
Volatile Organic

Abstract. The molecular composition and volatility of gaseous organic compounds were investigated during April–July 2019 at the Station for Measuring Ecosystem – Atmosphere Relations (SMEAR) II situated in a boreal forest in Hyytiälä, southern Finland. A Vocus proton-transfer-reaction time-of-flight mass spectrometer (Vocus PTR-ToF; hereafter Vocus) was deployed to measure volatile organic compounds (VOC) and less oxygenated VOC (i.e., OVOC). In addition, a multi-scheme chemical ionization inlet coupled to an atmospheric pressure interface time-of-flight mass spectrometer (MION APi-ToF) was used to detect less oxygenated VOC (using Br− as the reagent ion; hereafter MION-Br) and more oxygenated VOC (including highly oxygenated organic molecules, HOM; using NO3− as the reagent ion; hereafter MION-NO3). The comparison among different measurement techniques revealed that the highest elemental oxygen-to-carbon ratios (O : C) of organic compounds were observed by the MION-NO3 (0.9 ± 0.1, average ± 1 standard deviation), followed by the MION-Br (0.8 ± 0.1); and lowest by Vocus (0.2 ± 0.1). Diurnal patterns of the measured organic compounds were found to vary among different measurement techniques, even for compounds with the same molecular formula, suggesting contributions of different isomers detected by the different techniques and/or fragmentation from different parent compounds inside the instruments. Based on the complementary molecular information obtained from Vocus, MION-Br, and MION-NO3, a more complete picture of the bulk volatility of all measured organic compounds in this boreal forest was obtained. As expected, the VOC class was the most abundant (about 49.4 %), followed by intermediate-volatility organic compounds (IVOC, about 48.9 %). Although condensable organic compounds (low-volatility organic compounds, LVOC; extremely low-volatility organic compounds, ELVOC; and ultralow-volatility organic compounds, ULVOC) only comprised about 0.3 % of the total gaseous organic compounds, they play an important role in new particle formation as shown in previous studies in this boreal forest. Our study shows the full characterization of the gaseous organic compounds in the boreal forest and the advantages of combining Vocus and MION APi-ToF for measuring ambient organic compounds with different oxidation extent (from VOC to HOM). The results therefore provide a more comprehensive understanding of the molecular composition and volatility of atmospheric organic compounds as well as new insights in interpreting ambient measurements or testing/improving parameterizations in transport and climate models.

scholarly journals Measurement report: Molecular composition and volatility of gaseous organic compounds in a boreal forest – from volatile organic compounds to highly oxygenated organic molecules

2021 ◽  
Vol 21 (11) ◽  
pp. 8961-8977
Author(s):  
Wei Huang ◽  
Haiyan Li ◽  
Nina Sarnela ◽  
Liine Heikkinen ◽  
Yee Jun Tham ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Boreal Forest ◽  
Organic Compounds ◽  
Mass Spectrometer ◽  
Organic Molecules ◽  
Measurement Techniques ◽  
Time Of Flight ◽  
Molecular Composition ◽  
Complete Picture ◽  
Volatile Organic

Abstract. The molecular composition and volatility of gaseous organic compounds were investigated during April–July 2019 at the Station for Measuring Ecosystem – Atmosphere Relations (SMEAR) II situated in a boreal forest in Hyytiälä, southern Finland. In order to obtain a more complete picture and full understanding of the molecular composition and volatility of ambient gaseous organic compounds (from volatile organic compounds, VOCs, to highly oxygenated organic molecules, HOMs), two different instruments were used. A Vocus proton-transfer-reaction time-of-flight mass spectrometer (Vocus PTR-ToF; hereafter Vocus) was deployed to measure VOCs and less oxygenated VOCs (i.e., OVOCs). In addition, a multi-scheme chemical ionization inlet coupled to an atmospheric pressure interface time-of-flight mass spectrometer (MION API-ToF) was used to detect less oxygenated VOCs (using Br− as the reagent ion; hereafter MION-Br) and more oxygenated VOCs (including HOMs; using NO3- as the reagent ion; hereafter MION-NO3). The comparison among different measurement techniques revealed that the highest elemental oxygen-to-carbon ratios (O : C) of organic compounds were observed by the MION-NO3 (0.9 ± 0.1, average ± 1 standard deviation), followed by the MION-Br (0.8 ± 0.1); lowest O : C ratios were observed by Vocus (0.2 ± 0.1). Diurnal patterns of the measured organic compounds were found to vary among different measurement techniques, even for compounds with the same molecular formula, suggesting contributions of different isomers detected by the different techniques and/or fragmentation from different parent compounds inside the instruments. Based on the complementary molecular information obtained from Vocus, MION-Br, and MION-NO3, a more complete picture of the bulk volatility of all measured organic compounds in this boreal forest was obtained. As expected, the VOC class was the most abundant (about 53.2 %), followed by intermediate-volatility organic compounds (IVOCs, about 45.9 %). Although condensable organic compounds (low-volatility organic compounds, LVOCs; extremely low volatility organic compounds, ELVOCs; and ultralow-volatility organic compounds, ULVOCs) only comprised about 0.2 % of the total gaseous organic compounds, they play an important role in new particle formation as shown in previous studies in this boreal forest. Our study shows the full characterization of the gaseous organic compounds in the boreal forest and the advantages of combining Vocus and MION API-ToF for measuring ambient organic compounds with different oxidation extents (from VOCs to HOMs). The results therefore provide a more comprehensive understanding of the molecular composition and volatility of atmospheric organic compounds as well as new insights into interpreting ambient measurements or testing/improving parameterizations in transport and climate models.

Molecular composition and volatility of gaseous organic compounds in a boreal forest: from volatile organic compounds to highly oxygenated organic molecules

2021 ◽  
Author(s):  
Wei Huang ◽  
Haiyan Li ◽  
Nina Sarnela ◽  
Liine Heikkinen ◽  
Yee Jun Tham ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Boreal Forest ◽  
Organic Compounds ◽  
Mass Spectrometer ◽  
Organic Molecules ◽  
Measurement Techniques ◽  
Time Of Flight ◽  
Molecular Composition ◽  
Flight Mass Spectrometer ◽  
Volatile Organic

<p>The molecular composition and volatility of gaseous organic compounds were investigated during April–July 2019 at the Station for Measuring Ecosystem – Atmosphere Relations (SMEAR) II situated in a boreal forest in Hyytiälä, southern Finland. A Vocus proton-transfer-reaction time-of-flight mass spectrometer (Vocus PTR-ToF; hereafter Vocus) was deployed to measure volatile organic compounds (VOC) and less oxygenated VOC (i.e., OVOC). In addition, a multi-scheme chemical ionization inlet coupled to an atmospheric pressure interface time-of-flight mass spectrometer (MION APi-ToF) was used to detect less oxygenated VOC (using Br<sup>–</sup> as the reagent ion; hereafter MION-Br) and more oxygenated VOC (including highly oxygenated organic molecules, HOM; using NO<sub>3</sub><sup>–</sup> as the reagent ion; hereafter MION-NO<sub>3</sub>). The comparison among different measurement techniques revealed that the highest elemental oxygen-to-carbon ratios (O:C) of organic compounds were observed by the MION-NO<sub>3</sub> (0.9 ± 0.1, average ± 1 standard deviation), followed by the MION-Br (0.8 ± 0.1); and lowest by Vocus (0.2 ± 0.1). Diurnal patterns of the measured organic compounds were found to vary among different measurement techniques, even for compounds with the same molecular formula, suggesting contributions of different isomers detected by the different techniques and/or fragmentation from different parent compounds inside the instruments. Based on the complementary molecular information obtained from Vocus, MION-Br, and MION-NO<sub>3</sub>, a more complete picture of the bulk volatility of all measured organic compounds in this boreal forest was obtained. As expected, the VOC class was the most abundant (about 49.4 %), followed by intermediate-volatility organic compounds (IVOC, about 48.9 %). Although condensable organic compounds (low-volatility organic compounds, LVOC; extremely low-volatility organic compounds, ELVOC; and ultralow-volatility organic compounds, ULVOC) only comprised about 0.3 % of the total gaseous organic compounds, they play an important role in new particle formation as shown in previous studies in this boreal forest. Our study shows the full characterization of the gaseous organic compounds in the boreal forest and the advantages of combining Vocus and MION APi-ToF for measuring ambient organic compounds with different oxidation extent (from VOC to HOM). The results therefore provide a more comprehensive understanding of the molecular composition and volatility of atmospheric organic compounds as well as new insights in interpreting ambient measurements or testing/improving parameterizations in transport and climate models.</p><p><sub>Wei Huang and Haiyan Li contributed equally to this work.</sub></p><p><sub>Correspondence to: Wei Huang ([email protected]) and Federico Bianchi ([email protected])</sub></p>

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