Near-Infrared Laser Desorption/Ionization Aerosol Mass Spectrometry for Investigating Primary and Secondary Organic Aerosols under Low Loading Conditions†

2010 ◽  
Vol 82 (19) ◽  
pp. 7915-7923 ◽  
Author(s):  
Scott Geddes ◽  
Brian Nichols ◽  
Stevenson Flemer ◽  
Jessica Eisenhauer ◽  
James Zahardis ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Near Infrared ◽  
Secondary Organic Aerosols ◽  
Organic Aerosols ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Loading Conditions ◽  
Desorption Ionization ◽  
Aerosol Mass ◽  
Aerosol Mass Spectrometry

scholarly journals Near-infrared laser desorption/ionization aerosol mass spectrometry for measuring organic aerosol at atmospherically relevant aerosol mass loadings

2010 ◽  
Vol 3 (4) ◽  
pp. 1175-1183 ◽  
Author(s):  
S. Geddes ◽  
B. Nichols ◽  
K. Todd ◽  
J. Zahardis ◽  
G. A. Petrucci
Keyword(s):  
Mass Spectrometry ◽  
Near Infrared ◽  
Laser Desorption ◽  
Organic Aerosol ◽  
Infrared Laser ◽  
Laser Desorption Ionization ◽  
Desorption Ionization ◽  
Aerosol Mass ◽  
Aerosol Mass Spectrometry ◽  
Atmospherically Relevant

Abstract. A new method, near-infrared laser desorption/ionization aerosol mass spectrometry (NIR-LDI-AMS), is described for the real time analysis of organic aerosols at atmospherically relevant total mass loadings. Particles are sampled with an aerodynamic lens onto an aluminum probe. A moderate energy NIR laser pulse at 1064 nm is directed onto the probe to vaporize and ionize particle components. Delayed pulse extraction is then used to sample the ions into a reflectron time of flight mass spectrometer for chemical analysis. The soft ionization afforded by the NIR photons results in minimal fragmentation (loss of a hydrogen atom) producing intact pseudo-molecular anions at [M-H]−. The limit of detection measured for pure oleic acid particles (geometric mean diameter and standard deviation of 180 nm and 1.3, respectively) was 140 fg (or 1.7 ng m−3 per minute sampling time). As an example of the utility of NIR-LDI-AMS to measurements of atmospheric importance, the method was applied to laboratory chamber measurements of the secondary organic aerosol formation from ozonolysis of α-pinene. High quality mass spectra were recorded with a 2-min time resolution for total aerosol mass loadings ranging from 1.5 to 8.7 μg m−3. These results demonstrate the potential of NIR-LDI-AMS to allow for more accurate measurements of the organic fraction of atmospheric particulate at realistic mass loadings. Measurements at ambient-levels of SOA mass loading are important to improve parameterizations of chamber-based SOA formation for modeling regional and global SOA fluxes and to aid in remediating the discrepancy between modeled and observed atmospheric total SOA production rates and concentrations.

scholarly journals Near-infrared laser desorption/ionization aerosol mass spectrometry for measuring organic aerosol at atmospherically relevant aerosol mass loadings

2010 ◽  
Vol 3 (3) ◽  
pp. 2013-2033
Author(s):  
S. Geddes ◽  
B. Nichols ◽  
K. Todd ◽  
J. Zahardis ◽  
G. A. Petrucci
Keyword(s):  
Mass Spectrometry ◽  
Near Infrared ◽  
Laser Desorption ◽  
Organic Aerosol ◽  
Infrared Laser ◽  
Laser Desorption Ionization ◽  
Desorption Ionization ◽  
Aerosol Mass ◽  
Aerosol Mass Spectrometry ◽  
Atmospherically Relevant

Abstract. A new method, near-infrared laser desorption/ionization aerosol mass spectrometry (NIR-LDI-AMS), is described for the real time analysis of organic aerosols at atmospherically relevant total mass loadings. Particles are sampled with an aerodynamic lens onto an aluminium probe and moderate energy NIR laser pulse at 1064 nm is directed onto the probe to vaporize and ionize particle components. Delayed pulse extraction is then used to sample the ions into a reflectron time of flight mass spectrometer for chemical analysis. The soft ionization afforded by the NIR photons results in minimal fragmentation (loss of a hydrogen atom) producing intact pseudo-molecular anions at [M-H]−. The limit of detection measured for pure oleic acid particles (geometric mean diameter and standard deviation of 180 nm and 1.3, respectively) was 140 fg (or 1.7 ng m−3 per minute sampling time). As an example of the utility of NIR-LDI-AMS to measurements of atmospheric importance, the method was applied to laboratory chamber measurements of the secondary organic aerosol formation from ozonolysis of α-pinene. High quality mass spectra were recorded with a 2-min time resolution for total aerosol mass loadings ranging from 1.5 to 8.7 μg m−3. These results demonstrate the potential of NIR-LDI-AMS to allow for more accurate measurements of the organic fraction of atmospheric particulate at realistic mass loadings. Measurements at ambient-levels of SOA mass loading are important to improve parameterizations of chamber-based SOA formation for modeling regional and SOA fluxes and to aid in remediating the discrepancy between modeled and observed atmospheric total SOA production rates and concentrations.

Thermal Desorption/Tunable Vacuum–Ultraviolet Time-of-Flight Photoionization Aerosol Mass Spectrometry for Investigating Secondary Organic Aerosols in Chamber Experiments

2011 ◽  
Vol 83 (23) ◽  
pp. 9024-9032 ◽  
Author(s):  
Wenzheng Fang ◽  
Lei Gong ◽  
Xiaobin Shan ◽  
Fuyi Liu ◽  
Zhenya Wang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Thermal Desorption ◽  
Vacuum Ultraviolet ◽  
Secondary Organic Aerosols ◽  
Time Of Flight ◽  
Organic Aerosols ◽  
Aerosol Mass ◽  
Aerosol Mass Spectrometry

Online analysis of secondary organic aerosols from OH-initiated photooxidation and ozonolysis of α-pinene, β-pinene, Δ3-carene and d-limonene by thermal desorption–photoionisation aerosol mass spectrometry

2017 ◽  
Vol 14 (2) ◽  
pp. 75 ◽  
Author(s):  
Wenzheng Fang ◽  
Lei Gong ◽  
Liusi Sheng
Keyword(s):  
Mass Spectrometry ◽  
Thermal Desorption ◽  
Mass Spectra ◽  
Secondary Organic Aerosols ◽  
Organic Aerosols ◽  
Organic Aerosol ◽  
Oxidation Products ◽  
Online Analysis ◽  
Aerosol Mass ◽  
Aerosol Mass Spectrometry

Environmental contextSecondary organic aerosol, formed by oxidation of volatile precursors such as monoterpenes, is a major contributor to the total atmospheric organic aerosol. We focus on the online mass spectrometric analysis of the aerosol generated by oxidation products of four major monoterpenes in an environmental chamber. Numerous important monoterpene oxidation products were clearly observed and provided a direct comparison of the formation of biogenic secondary organic aerosols. AbstractWe present here thermal desorption–tunable vacuum ultraviolet time-of-flight photoionisation aerosol mass spectrometry (TD-VUV-TOF-PIAMS) for online analysis of biogenic secondary organic aerosols (BSOAs) formed from OH-initiated photooxidation and dark ozonolysis of α-pinene, β-pinene, Δ3-carene and d-limonene in smog chamber experiments. The ‘soft’ ionisation at near-threshold photon energies (≤10.5eV) used in this study permits direct measurement of the fairly clean mass spectra, facilitating molecular identification. The online BSOA mass spectra compared well with previous offline measurements and most of the important monoterpene oxidation products were clearly found in the online mass spectra. Oxidation products such as monoterpene-derived acids (e.g. pinic acid, pinonic acid, 3-caronic acid, limononic acid, limonalic acid), ketones (e.g. norpinone, limonaketone), aldehydes (e.g. caronaldehyde, norcaronaldehyde, limononaldehyde) and multifunctional organics (e.g. hydroxypinonaldehydes, hydroxy-3-caronic aldehydes, hydroxylimononic acid) were tentatively identified. The online TD-VUV-TOF-PIAMS mass spectra showed that the OH-initiated photooxidation and ozonolysis of the same monoterpenes produced some similar BSOA products; for example, 3-caric acid, 3-caronic acid, 3-norcaronic acid, 3-norcaralic acid, caronaldehyde and norcaronaldehyde were observed in both photooxidation and ozonolysis of Δ3-carene. However, they could be formed through different pathways. Some of the same products and isomers (e.g. 10-oxopinonic acid, pinonic acid, norpinic acid, hydroxyl pinonaldehyde, norpinonic acid, norpinone) were formed during the photooxidation and ozonolysis of α-pinene and β-pinene. However, several different BSOA products were generated in these photooxidation and ozonolysis reactions due to their different parent structures. The OH–monoterpene reaction generated higher-molecular-weight products than O3–monoterpene owing to multiple OH additions to the unsaturated carbon bond. The online observation of key BSOA products provided a direct comparison of BSOA formation among different monoterpenes and insights into the formation pathways in the OH-initiated photooxidation and ozonolysis of monoterpenes.

Identification of secondary organic aerosols based on aerosol mass spectrometry

2010 ◽  
Vol 53 (12) ◽  
pp. 2593-2599 ◽  
Author(s):  
XiaoFeng Huang ◽  
QianBiao Zhao ◽  
LingYan He ◽  
Min Hu ◽  
QiJing Bian ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Secondary Organic Aerosols ◽  
Organic Aerosols ◽  
Aerosol Mass ◽  
Aerosol Mass Spectrometry
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