scholarly journals The charging of neutral dimethylamine and dimethylamine–sulfuric acid clusters using protonated acetone

2015 ◽  
Vol 8 (6) ◽  
pp. 2577-2588
Author(s):  
K. Ruusuvuori ◽  
P. Hietala ◽  
O. Kupiainen-Määttä ◽  
T. Jokinen ◽  
H. Junninen ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Chemical Ionization ◽  
Lower Troposphere ◽  
Particle Formation ◽  
Atmospheric Conditions ◽  
Atmospheric Particle ◽  
Organic Bases ◽  
Atmospheric Nucleation ◽  
Quantum Chemical Methods ◽  
Vapour Concentration

Abstract. Sulfuric acid is generally considered one of the most important substances taking part in atmospheric particle formation. However, in typical atmospheric conditions in the lower troposphere, sulfuric acid and water alone are unable to form particles. It has been suggested that strong bases may stabilize sulfuric acid clusters so that particle formation may occur. More to the point, amines – strong organic bases – have become the subject of interest as possible cause for such stabilization. To probe whether amines play a role in atmospheric nucleation, we need to be able to measure accurately the gas-phase amine vapour concentration. Such measurements often include charging the neutral molecules and molecular clusters in the sample. Since amines are bases, the charging process should introduce a positive charge. This can be achieved by, for example, using chemical ionization with a positively charged reagent with a suitable proton affinity. In our study, we have used quantum chemical methods combined with a cluster dynamics code to study the use of acetone as a reagent ion in chemical ionization and compared the results with measurements performed with a chemical ionization atmospheric pressure interface time-of-flight mass spectrometer (CI-APi-TOF). The computational results indicate that protonated acetone is an effective reagent in chemical ionization. However, in the experiments the reagent ions were not depleted at the predicted dimethylamine concentrations, indicating that either the modelling scheme or the experimental results – or both – contain unidentified sources of error.

scholarly journals The charging of neutral dimethylamine and dimethylamine-sulphuric acid clusters using protonated acetone

2014 ◽  
Vol 7 (11) ◽  
pp. 11011-11044
Author(s):  
K. Ruusuvuori ◽  
P. Hietala ◽  
O. Kupiainen-Määttä ◽  
T. Jokinen ◽  
H. Junninen ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Chemical Ionization ◽  
Lower Troposphere ◽  
Particle Formation ◽  
Atmospheric Conditions ◽  
Atmospheric Particle ◽  
Organic Bases ◽  
Atmospheric Nucleation ◽  
Quantum Chemical Methods ◽  
Vapour Concentration

Abstract. Sulphuric acid is generally considered one of the most important substances taking part in atmospheric particle formation. However, in typical atmospheric conditions in the lower troposphere sulphuric acid and water alone are unable to form particles. It has been suggested that strong bases may stabilize sulphuric acid clusters so that particle formation may occur. More to the point, amines – strong organic bases – have become the subject of interest as possible cause for such stabilisation. To probe whether amines play a role in atmospheric nucleation, we need to be able to measure accurately the gas-phase amine vapour concentration. Such measurements often include charging the neutral molecules and molecular clusters in the sample. Since amines are bases, the charging process should introduce a positive charge. This can be achieved for example using a positively charged reagent with a suitable proton affinity. In our study, we have used quantum chemical methods combined with a cluster dynamics code to study the use of acetone as a reagent in chemical ionization and compared the results with measurements performed with a chemical ionization atmospheric pressure interface time-of-flight mass spectrometer (CI-APi-TOF). The computational results indicate that protonated acetone is an effective reagent in chemical ionization. However, in the experiments the charger ions were not depleted at the predicted dimethylamine concentrations, indicating that either the modelling scheme or the experimental results – or both – contain unidentified sources of error.

scholarly journals The effect of trimethylamine on atmospheric nucleation involving H<sub>2</sub>SO<sub>4</sub>

2010 ◽  
Vol 10 (11) ◽  
pp. 27673-27693 ◽  
Author(s):  
M. E. Erupe ◽  
A. A. Viggiano ◽  
S.-H. Lee
Keyword(s):  
Lower Troposphere ◽  
Particle Formation ◽  
Atmospheric Conditions ◽  
New Particle Formation ◽  
Critical Cluster ◽  
Organic Bases ◽  
Atmospheric Nucleation ◽  
Order Of Magnitude ◽  
Amine Compounds ◽  
Precursor Molecules

Abstract. Field observations and quantum chemical calculations have shown that organic amine compounds may be important in new particle formation processes involving H2SO4. Here, we report laboratory observations that investigate the effect of trimethylamine (TMA) on H2SO4-H2O nucleation made under aerosol precursor concentrations typically found in the lower troposphere ([H2SO4] of 106–107 cm−3; [TMA] of 180–1350 pptv). These results show that the threshold [H2SO4] needed to produce the unity nucleation rate ([H2SO4] of 106–107 cm−3) and the number of precursor molecules in the critical cluster (nH2SO4 = 4–6; nTMA = 1) are surprisingly similar to those found in the ammonia (NH3) ternary nucleation study (Benson et al., 2010a). At lower RH, however, enhancement in nucleation rates due to TMA was up to an order of magnitude greater than that due to NH3. These findings imply that both amines and NH3 are important nucleation species, but under dry atmospheric conditions, amines may have stronger effects on H2SO4 nucleation than NH3. Aerosol models should therefore take into account inorganic and organic bases together to fully understand the widespread new particle formation events in the lower troposphere.

scholarly journals The effect of trimethylamine on atmospheric nucleation involving H<sub>2</sub>SO<sub>4</sub>

2011 ◽  
Vol 11 (10) ◽  
pp. 4767-4775 ◽  
Author(s):  
M. E. Erupe ◽  
A. A. Viggiano ◽  
S.-H. Lee
Keyword(s):  
Quantum Chemical ◽  
Lower Troposphere ◽  
Particle Formation ◽  
Atmospheric Conditions ◽  
Organic Base ◽  
New Particle Formation ◽  
Organic Amine ◽  
Atmospheric Nucleation ◽  
Order Of Magnitude ◽  
Amine Compounds

Abstract. Field observations and quantum chemical calculations have shown that organic amine compounds may be important for new particle formation involving H2SO4. Here, we report laboratory observations that investigate the effect of trimethylamine (TMA) on H2SO4-H2O nucleation made under aerosol precursor concentrations typically found in the lower troposphere ([H2SO4] of 106−107 cm−3; [TMA] of 180–1350 pptv). The threshold [H2SO4] needed to produce the unity J was from 106−107 cm−3 and the slopes of Log J vs. Log [H2SO4] and Log J vs. Log [TMA] were 4–6 and 1, respectively, strikingly similar to the case of ammonia (NH3 ternary nucleation (Benson et al., 2011). At lower RH, however, enhancement in J due to TMA was up to an order of magnitude greater than that due to NH3. These findings imply that both amines and NH3 are important nucleation species, but under dry atmospheric conditions, amines may have stronger effects on H2SO4 nucleation than NH3. Aerosol models should therefore take into account inorganic and organic base compounds together to fully understand the widespread new particle formation events in the lower troposphere.

scholarly journals Chemical ionization of clusters formed from sulfuric acid and dimethylamine or diamines

2016 ◽  
Author(s):  
Coty N. Jen ◽  
Jun Zhao ◽  
Peter H. McMurry ◽  
David R. Hanson
Keyword(s):  
Sulfuric Acid ◽  
Chemical Ionization ◽  
Flow Reactor ◽  
Cluster Formation ◽  
Mass Spectrometers ◽  
Model Calculations ◽  
Molecule Reaction ◽  
Base Content ◽  
Atmospheric Nucleation ◽  
High Base

Abstract. Chemical ionization (CI) mass spectrometers are used to study atmospheric nucleation by detecting clusters produced by reactions of sulfuric acid and various basic gases. These instruments typically use nitrate to deprotonate and thus chemically ionize the clusters. In this study, we compare cluster concentrations measured using either nitrate or acetate. Clusters were formed in a flow reactor from vapors of sulfuric acid and dimethylamine, ethylene diamine, tetramethylethylene diamine, or butanediamine (also known as putrescine). These comparisons show that nitrate is unable to chemically ionize clusters with high base content. In addition, we vary the ion-molecule reaction time to probe ion processes which include proton-transfer, ion-molecule clustering, and decomposition of ions. Ion decomposition upon deprotonation by acetate/nitrate was observed. More studies are needed to quantify to what extent ion decomposition affects observed cluster content and concentrations, especially those chemically ionized with acetate since it deprotonates more types of clusters than nitrate. Model calculations of the neutral and ion cluster formation pathways are also presented to better identify the cluster types that are not efficiently deprotonated by nitrate. Comparison of model and measured clusters indicate that sulfuric acid dimer with two diamines and sulfuric acid trimer with two or more base molecules are not efficiently chemical ionized by nitrate. We conclude that acetate CI provides better information on cluster abundancies and their base content than nitrate CI.

scholarly journals Enhancing Potential of Trimethylamine Oxide on Atmospheric Particle Formation

Atmosphere ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 35 ◽  
Author(s):  
Nanna Myllys ◽  
Tuomo Ponkkonen ◽  
Sabrina Chee ◽  
James Smith
Keyword(s):  
Cluster Formation ◽  
Particle Formation ◽  
Formation Mechanisms ◽  
Atmospheric Particle ◽  
Dipole Interactions ◽  
Trimethylamine Oxide ◽  
Quantum Chemical Methods ◽  
Low Concentrations ◽  
Stable Clusters ◽  
Level Cluster

The role of an oxidation product of trimethylamine, trimethylamine oxide, in atmospheric particle formation is studied using quantum chemical methods and cluster formation simulations. Molecular-level cluster formation mechanisms are resolved, and theoretical results on particle formation are confirmed with mass spectrometer measurements. Trimethylamine oxide is capable of forming only one hydrogen bond with sulfuric acid, but unlike amines, trimethylamine oxide can form stable clusters via ion–dipole interactions. That is because of its zwitterionic structure, which causes a high dipole moment. Cluster growth occurs close to the acid:base ratio of 1:1, which is the same as for other monoprotic bases. Enhancement potential of trimethylamine oxide in particle formation is much higher than that of dimethylamine, but lower compared to guanidine. Therefore, at relatively low concentrations and high temperatures, guanidine and trimethylamine oxide may dominate particle formation events over amines.

scholarly journals Molecular understanding of atmospheric particle formation from sulfuric acid and large oxidized organic molecules

2013 ◽  
Vol 110 (43) ◽  
pp. 17223-17228 ◽  
Author(s):  
S. Schobesberger ◽  
H. Junninen ◽  
F. Bianchi ◽  
G. Lonn ◽  
M. Ehn ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Organic Molecules ◽  
Particle Formation ◽  
Atmospheric Particle

scholarly journals Chemical ionization of clusters formed from sulfuric acid and dimethylamine or diamines

2016 ◽  
Vol 16 (19) ◽  
pp. 12513-12529 ◽  
Author(s):  
Coty N. Jen ◽  
Jun Zhao ◽  
Peter H. McMurry ◽  
David R. Hanson
Keyword(s):  
Sulfuric Acid ◽  
Reaction Time ◽  
Chemical Ionization ◽  
Flow Reactor ◽  
Cluster Formation ◽  
Mass Spectrometers ◽  
Molecule Reaction ◽  
Base Content ◽  
Atmospheric Nucleation ◽  
High Base

Abstract. Chemical ionization (CI) mass spectrometers are used to study atmospheric nucleation by detecting clusters produced by reactions of sulfuric acid and various basic gases. These instruments typically use nitrate to deprotonate and thus chemically ionize the clusters. In this study, we compare cluster concentrations measured using either nitrate or acetate. Clusters were formed in a flow reactor from vapors of sulfuric acid and dimethylamine, ethylene diamine, tetramethylethylene diamine, or butanediamine (also known as putrescine). These comparisons show that nitrate is unable to chemically ionize clusters with high base content. In addition, we vary the ion–molecule reaction time to probe ion processes which include proton-transfer, ion–molecule clustering, and decomposition of ions. Ion decomposition upon deprotonation by acetate/nitrate was observed. More studies are needed to quantify to what extent ion decomposition affects observed cluster content and concentrations, especially those chemically ionized with acetate since it deprotonates more types of clusters than nitrate.Model calculations of the neutral and ion cluster formation pathways are also presented to better identify the cluster types that are not efficiently deprotonated by nitrate. Comparison of model and measured clusters indicate that sulfuric acid dimers with two diamines and sulfuric acid trimers with two or more base molecules are not efficiently chemical ionized by nitrate. We conclude that acetate CI provides better information on cluster abundancies and their base content than nitrate CI.

scholarly journals Measurement of iodine species and sulfuric acid using bromide chemical ionization mass spectrometers

2020 ◽  
Author(s):  
Mingyi Wang ◽  
Xu-Cheng He ◽  
Henning Finkenzeller ◽  
Siddharth Iyer ◽  
Dexian Chen ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Chemical Ionization ◽  
Detection Limits ◽  
Particle Formation ◽  
Cloud Chamber ◽  
Ionization Mass ◽  
New Particle Formation ◽  
Reduced Pressure ◽  
Mass Spectrometers ◽  
Iodine Species

Abstract. Iodine species are important in the marine atmosphere for oxidation and new-particle formation. Understanding iodine chemistry and iodine new-particle formation requires high time resolution, high sensitivity, and simultaneous measurements of many iodine species. Here, we describe the application of bromide chemical ionization mass spectrometers (Br-CIMS) to this task. During iodine new-particle formation experiments in the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber, we have measured gas-phase iodine species and sulfuric acid using two Br-CIMS, one coupled to a Multi-scheme chemical IONization inlet (Br-MION-CIMS) and the other to a Filter Inlet for Gasses and AEROsols inlet (Br-FIGAERO-CIMS). From offline calibrations and inter-comparisons with other instruments attached to the CLOUD chamber, we have quantified the sensitivities of the Br-MION-CIMS to HOI, I2, and H2SO4 and obtain detection limits of 5.8 × 106, 6.3 × 105, and 2.0 × 105 molec cm−3, respectively, for a 2-min integration time. From binding energy calculations, we estimate the detection limit for HIO3 to be 1.2 × 105 molec cm−3, based on an assumption of maximum sensitivity. Detection limits in the Br-FIGAERO-CIMS are around one order of magnitude higher than those in the Br-MION-CIMS; for example, the detection limits for HOI and HIO3 are 3.3 × 107 and 5.1 × 106 molec cm−3, respectively. Our comparisons of the performance of the MION inlet and the FIGAERO inlet show that bromide chemical ionization mass spectrometers using either atmospheric pressure or reduced pressure interfaces are well-matched to measuring iodine species and sulfuric acid in marine environments.

scholarly journals On the formation of sulphuric acid-amine clusters in varying atmospheric conditions and its influence on atmospheric new particle formation

2012 ◽  
Vol 12 (5) ◽  
pp. 11485-11537 ◽  
Author(s):  
P. Paasonen ◽  
T. Olenius ◽  
O. Kupiainen ◽  
T. Kurtén ◽  
T. Petäjä ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Sulphuric Acid ◽  
Acid Concentration ◽  
Formation Rate ◽  
Particle Formation ◽  
Atmospheric Conditions ◽  
New Particle Formation ◽  
Atmospheric Particle ◽  
Atmospheric Observations ◽  
Sulphuric Acid Concentration

Abstract. Sulphuric acid is a key component in atmospheric new particle formation. However, sulphuric acid alone does not form stable enough clusters to initiate particle formation in atmospheric conditions. Strong bases, such as amines, have been suggested to stabilize sulphuric acid clusters and thus participate in particle formation. We modelled the formation rate of clusters with two sulphuric acid and two amine molecules (JA2B2) at varying atmospherically relevant conditions with respect to concentrations of sulphuric acid ([H2SO4]), dimethylamine ([DMA]) and trimethylamine ([TMA]), temperature and relative humidity (RH). The modelled formation rates JA2B2 were functions of sulphuric acid concentration with close to quadratic dependence, which is in good agreement with atmospheric observations of the connection between the particle formation rate and sulphuric acid concentration. The coefficients KA2B2 connecting the cluster formation rate and sulphuric acid concentrations as JA2B2 = KA2B2[H2SO4]2 turned out to depend also on amine concentrations, temperature and relative humidity. We tested how the model results change if the clusters with two sulphuric acid and two amine molecules are assumed to act as seeds for heterogeneous nucleation of organic vapours (other than amines) with higher atmospheric concentrations than sulphuric acid. We also compared the modelled coefficients KA2B2 with the corresponding coefficients calculated from the atmospheric observations (Kobs) from environments with varying temperatures and levels of anthropogenic influence. By taking into account the modelled behaviour of JA2B2 as a function of [H2SO4], temperature and RH, the atmospheric particle formation rate was reproduced more closely than with the traditional semi-empirical formulae based on sulphuric acid concentration only. The formation rates of clusters with two sulphuric acid and two amine molecules with different amine compositions (DMA or TMA or one of both) had different responses to varying meteorological conditions and concentrations of vapours participating to particle formation. The observed inverse proportionality of the coefficient Kobs with RH and temperature agreed best with the modelled coefficient KA2B2 related to formation of a~cluster with two H2SO4 and one or two TMA molecules, assuming that these clusters can grow in collisions with abundant organic vapour molecules. In case this assumption is valid, our results suggest that the formation rate of clusters with at least two of both sulphuric acid and amine molecules might be the rate-limiting step for atmospheric particle formation. More generally, our analysis elucidates the sensitivity of the atmospheric particle formation rate to meteorological variables and concentrations of vapours participating in particle formation (also other than H2SO4).

scholarly journals Measurement of iodine species and sulfuric acid using bromide chemical ionization mass spectrometers

2021 ◽  
Vol 14 (6) ◽  
pp. 4187-4202
Author(s):  
Mingyi Wang ◽  
Xu-Cheng He ◽  
Henning Finkenzeller ◽  
Siddharth Iyer ◽  
Dexian Chen ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Chemical Ionization ◽  
Detection Limits ◽  
Particle Formation ◽  
High Time Resolution ◽  
Ionization Mass ◽  
New Particle Formation ◽  
Reduced Pressure ◽  
Mass Spectrometers ◽  
Iodine Species

Abstract. Iodine species are important in the marine atmosphere for oxidation and new-particle formation. Understanding iodine chemistry and iodine new-particle formation requires high time resolution, high sensitivity, and simultaneous measurements of many iodine species. Here, we describe the application of a bromide chemical ionization mass spectrometer (Br-CIMS) to this task. During the iodine oxidation experiments in the Cosmics Leaving OUtdoor Droplets (CLOUD) chamber, we have measured gas-phase iodine species and sulfuric acid using two Br-CIMS, one coupled to a Multi-scheme chemical IONization inlet (Br-MION-CIMS) and the other to a Filter Inlet for Gasses and AEROsols inlet (Br-FIGAERO-CIMS). From offline calibrations and intercomparisons with other instruments, we have quantified the sensitivities of the Br-MION-CIMS to HOI, I2, and H2SO4 and obtained detection limits of 5.8 × 106, 3.8 × 105, and 2.0 × 105 molec. cm−3, respectively, for a 2 min integration time. From binding energy calculations, we estimate the detection limit for HIO3 to be 1.2 × 105 molec. cm−3, based on an assumption of maximum sensitivity. Detection limits in the Br-FIGAERO-CIMS are around 1 order of magnitude higher than those in the Br-MION-CIMS; for example, the detection limits for HOI and HIO3 are 3.3 × 107 and 5.1 × 106 molec. cm−3, respectively. Our comparisons of the performance of the MION inlet and the FIGAERO inlet show that bromide chemical ionization mass spectrometers using either atmospheric pressure or reduced pressure interfaces are well-matched to measuring iodine species and sulfuric acid in marine environments.

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