Composition of Ultrafine Particles in Urban Beijing: Measurement Using a Thermal Desorption Chemical Ionization Mass Spectrometer

2021 ◽  
Author(s):  
Xiaoxiao Li ◽  
Yuyang Li ◽  
Michael J. Lawler ◽  
Jiming Hao ◽  
James N. Smith ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Thermal Desorption ◽  
Ultrafine Particles ◽  
Chemical Ionization ◽  
Ionization Mass ◽  
Desorption Chemical Ionization

Composition of ultrafine particles in urban Beijing: Measurement using a thermal desorption chemical ionization mass spectrometer

2021 ◽  
Author(s):  
Xiaoxiao Li ◽  
Yuyang Li ◽  
Michael Lawler ◽  
Jiming Hao ◽  
James Smith ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Thermal Desorption ◽  
Ultrafine Particles ◽  
Chemical Ionization ◽  
Urban Atmosphere ◽  
Ionization Mass ◽  
Radioactive Materials ◽  
Desorption Chemical Ionization ◽  
Wide Range ◽  
Primary Emissions

<p>Ultrafine particles (UFPs) dominate the particle number population in the urban atmosphere and revealing their chemical composition is important. The thermal desorption chemical ionization mass spectrometer (TDCIMS) can semi-continuously measure UFP composition at the molecular level. We modified a TDCIMS and deployed it in urban Beijing. Radioactive materials in the TDCIMS for aerosol charging and chemical ionization were replaced by soft X-ray ionizers so that it can be operated in countries with tight regulations on radioactive materials. Protonated N-methyl-2-pyrrolidone ions were used as the positive reagent ion, which selectively detects ammonia and low-molecular weight-aliphatic amines and amides vaporized from the particle phase. With superoxide as the negative reagent ion, a wide range of inorganic and organic compounds were observed, including nitrate, sulfate, aliphatic acids with carbon numbers up to 18, and highly oxygenated CHO, CHON, and CHOS compounds. The latter two can be attributed to parent ions or the decomposition products of organonitrates and organosulfates/organosulfonates, respectively. Components from both primary emissions and secondary formation of UFPs were identified. Compared to the UFPs measured at forest and marine sites, those in urban Beijing contain more nitrogen-containing and sulfur-containing compounds. These observations illustrate unique features of the UFPs in this polluted urban environment and provide insights into their origins.</p>

scholarly journals Size Resolved Online Chemical Analysis of Nano Aerosol Particles: A Thermal Desorption Differential Mobility Analyzer Coupled to a Chemical Ionization Time Of Flight Mass Spectrometer

2018 ◽  
Author(s):  
Andrea C. Wagner ◽  
Anton Bergen ◽  
Sophia Brilke ◽  
Claudia Fuchs ◽  
Markus Ernst ◽  
...  
Keyword(s):  
Chemical Analysis ◽  
Mass Spectrometer ◽  
Thermal Desorption ◽  
Chemical Ionization ◽  
Aerosol Particles ◽  
Transmission Efficiency ◽  
Test Substance ◽  
Ionization Mass ◽  
Differential Mobility Analyzer ◽  
Differential Mobility

Abstract. A new method for size resolved chemical analysis of nucleation mode aerosol particles (size range from ~ 10 to ~ 30 nm) is presented. The Thermal Desorption Differential Mobility Analyzer (TD-DMA) uses an online, discontinuous principle. The particles are charged, a specific size is selected by differential mobility analysis and they are collected on a filament by electrostatic precipitation. Subsequently, the sampled mass is evaporated in a clean carrier gas and analyzed by a chemical ionization mass spectrometer. Gas phase measurements are performed with the same mass spectrometer during the sampling of particles. The characterization shows reproducible results, with a particle size resolution of 1.19 and the transmission efficiency for 15 nm particles being slightly above 50 %. The signal from the evaporation of a test substance can be detected starting from 0.01 ng and shows a linear response in the mass spectrometer. Instrument operation in the range of pg/m3 is demonstrated by an example measurement of 15 nm particles produced by nucleation from dimethylamine, sulfuric acid and water.

scholarly journals Size-resolved online chemical analysis of nanoaerosol particles: a thermal desorption differential mobility analyzer coupled to a chemical ionization time-of-flight mass spectrometer

2018 ◽  
Vol 11 (10) ◽  
pp. 5489-5506 ◽  
Author(s):  
Andrea C. Wagner ◽  
Anton Bergen ◽  
Sophia Brilke ◽  
Claudia Fuchs ◽  
Markus Ernst ◽  
...  
Keyword(s):  
Chemical Analysis ◽  
Mass Spectrometer ◽  
Thermal Desorption ◽  
Chemical Ionization ◽  
Transmission Efficiency ◽  
Test Substance ◽  
Ionization Mass ◽  
Differential Mobility Analyzer ◽  
Differential Mobility ◽  
Phase Measurements

Abstract. A new method for size-resolved chemical analysis of nucleation mode aerosol particles (size range from ∼10 to ∼30 nm) is presented. The Thermal Desorption Differential Mobility Analyzer (TD-DMA) uses an online, discontinuous principle. The particles are charged, a specific size is selected by differential mobility analysis and they are collected on a filament by electrostatic precipitation. Subsequently, the sampled mass is evaporated in a clean carrier gas and analyzed by a chemical ionization mass spectrometer. Gas-phase measurements are performed with the same mass spectrometer during the sampling of particles. The characterization shows reproducible results, with a particle size resolution of 1.19 and the transmission efficiency for 15 nm particles being slightly above 50 %. The signal from the evaporation of a test substance can be detected starting from 0.01 ng and shows a linear response in the mass spectrometer. Instrument operation in the range of pg m−3 is demonstrated by an example measurement of 15 nm particles produced by nucleation from dimethylamine, sulfuric acid and water.

scholarly journals Composition of 15–85 nm particles in marine air

2014 ◽  
Vol 14 (21) ◽  
pp. 11557-11569 ◽  
Author(s):  
M. J. Lawler ◽  
J. Whitehead ◽  
C. O'Dowd ◽  
C. Monahan ◽  
G. McFiggans ◽  
...  
Keyword(s):  
Growth Factors ◽  
Chemical Composition ◽  
Benzoic Acid ◽  
Thermal Desorption ◽  
Chemical Ionization ◽  
Particle Number ◽  
Sea Salt ◽  
Ionization Mass ◽  
Desorption Chemical Ionization ◽  
Marine Air

Abstract. The chemical composition of 15–85 nm diameter particles was measured at Mace Head, Ireland, during May 2011 using the TDCIMS (thermal desorption chemical ionization mass spectrometer). Measurable levels of chloride, sodium, and sulfate were present in essentially all collected samples of these particles at this coastal Atlantic site. Acetaldehyde and benzoic acid were also frequently detected. Concomitant particle hygroscopicity observations usually showed a sea-salt mode and a lower hygroscopicity mode with growth factors near to that of ammonium sulfate. There were many periods lasting from hours to about 2 days during which the 10–60 nm particle number increased dramatically in polar oceanic air. These periods were correlated with the presence of benzoic acid in the particles and an increase in the number of lower hygroscopicity mode particles. Very small (< 10 nm) particles were also present, suggesting that new particle formation contributed to these nanoparticle enhancement events.

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