scholarly journals A novel inlet system for on-line chemical analysis of semi-volatile submicron particulate matter

2014 ◽  
Vol 7 (9) ◽  
pp. 10109-10130 ◽  
Author(s):  
P. Eichler ◽  
M. Müller ◽  
B. D'Anna ◽  
A. Wisthaler
Keyword(s):  
Chemical Analysis ◽  
Gas Phase ◽  
Chemical Characterization ◽  
Proton Transfer Reaction ◽  
Molecular Ions ◽  
Submicron Particles ◽  
Inlet System ◽  
On Line ◽  
Set Up ◽  
Organic Analytes

Abstract. We herein present the concept of a novel modular inlet system that allows using gas-phase analyzers for on-line chemical characterization of semi-volatile submicron particles. The "chemical analysis of aerosol on-line" (CHARON) inlet consists of a gas-phase denuder for stripping off gas-phase analytes, an aerodynamic lens for particle enrichment in the sampling flow and a thermo-desorption unit for particle volatilization prior to chemical analysis. We coupled the CHARON inlet to a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) which quantitatively detects most organic analytes and ammonia. The combined set-up measures submicron organic and ammonium nitrate/sulfate particles online. Two proof-of-principle studies were carried out for demonstrating the analytical power of the new set-up in analyzing primarily emitted and secondarily generated particles. Oxygenated organics and their partitioning between the gas and the particulate phase were observed from the reaction of limonene with ozone. Abundant quasi-molecular ions of organic particulate constituents were observed when submicron particles were sampled from diluted mainstream cigarette smoke.

scholarly journals A novel inlet system for online chemical analysis of semi-volatile submicron particulate matter

2015 ◽  
Vol 8 (3) ◽  
pp. 1353-1360 ◽  
Author(s):  
P. Eichler ◽  
M. Müller ◽  
B. D'Anna ◽  
A. Wisthaler
Keyword(s):  
Chemical Analysis ◽  
Real Time ◽  
Gas Phase ◽  
Chemical Characterization ◽  
Proton Transfer Reaction ◽  
Submicron Particles ◽  
Average Particle ◽  
Inlet System ◽  
Organic Analytes ◽  
Tof Ms

Abstract. We herein present a novel modular inlet system designed to be coupled to low-pressure gas analyzers for online chemical characterization of semi-volatile submicron particles. The "chemical analysis of aerosol online" (CHARON) inlet consists of a gas-phase denuder for stripping off gas-phase analytes, an aerodynamic lens for particle collimation combined with an inertial sampler for the particle-enriched flow and a thermodesorption unit for particle volatilization prior to chemical analysis. The denuder was measured to remove gas-phase organics with an efficiency > 99.999% and to transmit particles in the 100–750 nm size range with a 75–90% efficiency. The measured average particle enrichment factor in the subsampling flow from the aerodynamic lens was 25.6, which is a factor of 3 lower than the calculated theoretical optimum. We coupled the CHARON inlet to a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) which quantitatively detects most organic analytes and ammonia. The combined CHARON-PTR-ToF-MS setup is thus capable of measuring both the organic and the ammonium fraction in submicron particles in real time. Individual organic compounds can be detected down to levels of 10–20 ng m−3. Two proof-of-principle studies were carried out for demonstrating the analytical power of this new instrumental setup: (i) oxygenated organics and their partitioning between the gas and the particulate phase were observed from the reaction of limonene with ozone and (ii) nicotine was measured in cigarette smoke particles demonstrating that selected organic target compounds can be detected in submicron particles in real time.

scholarly journals MS/MS studies for the selective detection of isomeric biogenic VOCs using a Townsend Discharge Triple Quadrupole Tandem MS and a PTR-Linear Ion Trap MS

2009 ◽  
Vol 2 (4) ◽  
pp. 1837-1861 ◽  
Author(s):  
M. Müller ◽  
L. H. Mielke ◽  
M. Breitenlechner ◽  
S. A. McLuckey ◽  
P. B. Shepson ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Ion Trap ◽  
Proton Transfer Reaction ◽  
High Energy ◽  
Molecular Ions ◽  
Ion Source ◽  
Linear Ion Trap ◽  
Triple Quadrupole ◽  
On Line ◽  
Townsend Discharge

Abstract. We performed MS/MS investigations of biogenic volatile organic compounds (BVOC) using a triple quadrupole tandem mass spectrometer (QqQ-MS) equipped with a Townsend Discharge ion source and a Proton Transfer Reaction Linear Ion Trap (PTR-LIT) mass spectrometer. Both instruments use H2O chemical ionization to produce protonated molecular ions. Here we report a study of the application of these instruments to determine methyl vinyl ketone (MVK) and methacrolein (MACR) and a series of monoterpenes (α-pinene, β-pinene, 3-carene, limonene, myrcene, ocimene) and sesquiterpenes (humulene and farnesene). Both instruments achieved sub-ppb detection limits in the single MS mode and in the MS/MS mode for differentiating MVK and MACR. Collision induced dissociation (CID) of protonated monoterpenes and sesquiterpenes was studied under the high-energy, single-to-few collision conditions of the QqQ-MS instrument and under the low-energy, multiple collision conditions of the PTR-LIT. Differences and similarities in the breakdown curves obtained are discussed. In addition, we performed MS4 of protonated limonene to illustrate the analytical power of the PTR-LIT. In spite of the progress we have made, the selective on-line mass-spectrometric detection of individual monoterpenes or sesquiterpenes in complex mixtures currently does not yet seem to be possible.

scholarly journals MS/MS studies on the selective on-line detection of sesquiterpenes using a Flowing Afterglow–Tandem Mass Spectrometer (FA-TMS)

2011 ◽  
Vol 4 (4) ◽  
pp. 669-681 ◽  
Author(s):  
J. Rimetz-Planchon ◽  
F. Dhooghe ◽  
N. Schoon ◽  
F. Vanhaecke ◽  
C. Amelynck
Keyword(s):  
Mass Spectrometer ◽  
Chemical Ionization ◽  
Transfer Reaction ◽  
Proton Transfer Reaction ◽  
Molecular Ions ◽  
Line Detection ◽  
Tandem Mass ◽  
Flowing Afterglow ◽  
Tandem Mass Spectrometer ◽  
On Line

Abstract. A Flowing Afterglow-Tandem Mass Spectrometer (FA-TMS) was used to investigate the feasibility of selective on-line detection of a series of seven sesquiterpenes (SQTs). These SQTs were chemically ionized by either H3O+ or NO+ reagent ions in the FA, resulting among others in protonated SQT and SQT molecular ions, respectively. These and other Chemical Ionization (CI) product ions were subsequently subjected to dissociation by collisions with Ar atoms in the collision cell of the tandem mass spectrometer. The fragmentation spectra show similarities with mass spectra obtained for these compounds with other instruments such as a Proton Transfer Reaction-Linear Ion Trap (PTR-LIT), a Proton Transfer Reaction-Mass Spectrometer (PTR-MS), a Triple Quadrupole-Mass Spectrometer (QqQ-MS) and a Selected Ion Flow Tube-Mass Spectrometer (SIFT-MS). Fragmentation of protonated SQT is characterized by fragment ions at the same masses but with different intensities for the individual SQT. Distinction of SQTs is based on well-chosen intensity ratios and collision energies. The fragmentation patterns of SQT molecular ions show specific fragment ion tracers at m/z 119, m/z162, m/z 137 and m/z 131 for α-cedrene, δ-neoclovene, isolongifolene and α-humulene, respectively. Consequently, chemical ionization of SQT by NO+, followed by MS/MS of SQT+ seems to open a way for selective quantification of SQTs in mixtures.

scholarly journals The Comparative Reactivity Method – a new tool to measure total OH Reactivity in ambient air

2008 ◽  
Vol 8 (8) ◽  
pp. 2213-2227 ◽  
Author(s):  
V. Sinha ◽  
J. Williams ◽  
J. N. Crowley ◽  
J. Lelieveld
Keyword(s):  
Dynamic Range ◽  
Field Tests ◽  
Ambient Air ◽  
Proton Transfer Reaction ◽  
Vital Role ◽  
Oh Radicals ◽  
Current Configuration ◽  
Sink Term ◽  
On Line ◽  
Set Up

Abstract. Hydroxyl (OH) radicals play a vital role in maintaining the oxidizing capacity of the atmosphere. To understand variations in OH radicals both source and sink terms must be understood. Currently the overall sink term, or the total atmospheric reactivity to OH, is poorly constrained. Here, we present a new on-line method to directly measure the total OH reactivity (i.e.~total loss rate of OH radicals) in a sampled air mass. In this method, a reactive molecule (X), not normally present in air, is passed through a glass reactor and its concentration is monitored with a suitable detector. OH radicals are then introduced in the glass reactor at a constant rate to react with X, first in the presence of zero air and then in the presence of ambient air containing VOCs and other OH reactive species. Comparing the amount of X exiting the reactor with and without the ambient air allows the air reactivity to be determined. In our existing set up, X is pyrrole and the detector used is a proton transfer reaction mass spectrometer. The present dynamic range for ambient air reactivity is about 6 to 300 s−1, with an overall maximum uncertainty of 25% above 8 s−1 and up to 50% between 6–8 s−1. The system has been tested and calibrated with different single and mixed hydrocarbon standards showing excellent linearity and accountability with the reactivity of the standards. Potential interferences such as high NO in ambient air, varying relative humidity and photolysis of pyrrole within the setup have also been investigated. While interferences due changing humidity and photolysis of pyrrole are easily overcome by ensuring that humidity in the set up does not change drastically and the photolytic loss of pyrrole is measured and taken into account, respectively, NO>10 ppb in ambient air remains a significant interference for the current configuration of the instrument. Field tests in the tropical rainforest of Suriname (~53 s

scholarly journals A new aerosol collector for quasi on-line analysis of particulate organic matter: the Aerosol Collection Module (ACM) and first applications with a GC/MS-FID

2010 ◽  
Vol 3 (5) ◽  
pp. 1423-1436 ◽  
Author(s):  
T. Hohaus ◽  
D. Trimborn ◽  
A. Kiendler-Scharr ◽  
I. Gensch ◽  
W. Laumer ◽  
...  
Keyword(s):  
Organic Matter ◽  
Gas Phase ◽  
Phase Transfer ◽  
Collection Efficiency ◽  
Aerosol Particles ◽  
High Vacuum ◽  
Chemical Characterization ◽  
Organic Aerosol ◽  
Ambient Aerosols ◽  
On Line

Abstract. In many environments organic matter significantly contributes to the composition of atmospheric aerosol particles influencing its properties. Detailed chemical characterization of ambient aerosols is critical in order to understand the formation process, composition, and properties of aerosols and facilitates source identification and relative contributions from different types of sources to ambient aerosols in the atmosphere. However, current analytical methods are far from full speciation of organic aerosols and often require sampling times of up to one week. Offline methods are also subjected to artifacts during aerosol collection and storage. In the present work a new technique for quasi on-line compound specific measurements of organic aerosol particles was developed. The Aerosol Collection Module (ACM) focuses particles into a beam which is directed to a cooled sampling surface. The sampling takes place in a high vacuum environment where the gas phase from the sample volume is removed. After collection is completed volatile and semi-volatile compounds are evaporated from the collection surface through heating and transferred to a detector. For laboratory characterization the ACM was interfaced with a Gas Chromatograph Mass Spectrometer, Flame Ionization Detector system (GC/MS-FID), abbreviated as ACM GC-MS. The particle collection efficiency, gas phase transfer efficiency, and linearity of the ACM GC-MS were determined using laboratory generated octadecane aerosols. The ACM GC-MS is linear over the investigated mass range of 10 to 100 ng and a recovery rate of 100% was found for octadecane particles. The ACM GC-MS was applied to investigate secondary organic aerosol (SOA) formed from β-pinene oxidation. Nopinone, myrtanal, myrtenol, 1-hydroxynopinone, 3-oxonopinone, 3,7-dihydroxynopinone, and bicyclo[3,1,1]hept-3-ene-2-one were found as products in the SOA. The ACM GC-MS results are compared to quartz filter samples taken in parallel to the ACM GC-MS measurements. First measurements of ambient atmospheric aerosols are presented.

Simultaneous on-line size and chemical analysis of gas phase and particulate phase of cigarette mainstream smoke

2009 ◽  
Vol 394 (4) ◽  
pp. 1193-1203 ◽  
Author(s):  
Thomas Adam ◽  
John McAughey ◽  
Conor McGrath ◽  
Christoph Mocker ◽  
Ralf Zimmermann
Keyword(s):  
Chemical Analysis ◽  
Gas Phase ◽  
Mainstream Smoke ◽  
Particulate Phase ◽  
On Line ◽  
Cigarette Mainstream Smoke

scholarly journals MS/MS studies on the selective on-line detection of sesquiterpenes using a flowing afterglow-tandem mass spectrometer

2010 ◽  
Vol 3 (5) ◽  
pp. 4285-4311 ◽  
Author(s):  
J. Rimetz-Planchon ◽  
F. Dhooghe ◽  
N. Schoon ◽  
F. Vanhaecke ◽  
C. Amelynck
Keyword(s):  
Mass Spectrometer ◽  
Chemical Ionization ◽  
Transfer Reaction ◽  
Proton Transfer Reaction ◽  
Molecular Ions ◽  
Line Detection ◽  
Tandem Mass ◽  
Flowing Afterglow ◽  
Tandem Mass Spectrometer ◽  
On Line

Abstract. A Flowing Afterglow-Tandem Mass Spectrometer (FA-TMS) was used to investigate the feasibility of selective on-line detection of a series of seven sesquiterpenes (SQTs). These SQTs were chemically ionized by either H3O+ or NO+ reagent ions in the FA, resulting among others in protonated SQT and SQT molecular ions, respectively. These and other Chemical Ionization (CI) product ions were subsequently subjected to dissociation by collisions with Ar atoms in the collision cell of the tandem mass spectrometer. The fragmentation spectra show similarities with mass spectra obtained for these compounds with other instruments such as a Proton Transfer Reaction-Linear Ion Trap (PTR-LIT), a Proton Transfer Reaction-Mass Spectrometer (PTR-MS), a Triple Quadrupole-Mass Spectrometer (QqQ-MS) and a Selected Ion Flow Tube-Mass Spectrometer (SIFT-MS). Fragmentation of protonated SQT is characterized by fragment ions at the same masses but with different intensities for the individual SQT. Distinction of SQTs is based on well-chosen intensity ratios and collision energies. The fragmentation patterns of SQT molecular ions show specific fragment ion tracers at m/z 119, m/z 162, m/z 137 and m/z 131 for α-cedrene, δ-neoclovene, isolongifolene and α-humulene, respectively. Consequently, chemical ionization of SQT by NO+, followed by MS/MS of SQT+ seems to open a way for selective quantification of SQTs in mixtures.

Radiation less transitions in gas phase molecular ions

1980 ◽  
Vol 77 ◽  
pp. 705-718 ◽  
Author(s):  
Sydney Leach ◽  
Gérald Dujardin ◽  
Guy Taieb
Keyword(s):  
Gas Phase ◽  
Molecular Ions
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