Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published October 20, 2020 | Supplemental Material
Journal Article Open

Coupling Filter-Based Thermal Desorption Chemical Ionization Mass Spectrometry with Liquid Chromatography/Electrospray Ionization Mass Spectrometry for Molecular Analysis of Secondary Organic Aerosol


Filter-based thermal desorption (F-TD) techniques, such as the filter inlet for gases and aerosols, are widely employed to investigate the molecular composition and physicochemical properties of secondary organic aerosol (SOA). Here, we introduce an enhanced capability of F-TD through the combination of a customized F-TD inlet with chemical ionization mass spectrometry (CIMS) and ultraperformance liquid chromatography/electrospray ionization mass spectrometry (UPLC/ESI-MS). The utility of F-TD/CIMS + UPLC/ESI-MS is demonstrated by application to α-pinene ozonolysis SOA for which increased filter aerosol mass loading is shown to slow the evaporation rates of deposited compounds. Evidence for oligomer decomposition producing multimode F-TD/CIMS thermograms is provided by the measurement of the mass fraction remaining of monomeric and dimeric α-pinene oxidation products on the filter via UPLC/ESI-MS. In situ evaporation of aerosol particles suggests that α-pinene-derived hydroperoxides are thermally labile; thus, analysis of particle-phase (hydro)peroxides via F-TD may not be appropriate. A synthesized pinene-derived dimer ester (C₂₀H₃₂O₅) is found to be thermally stable up to 200 °C, whereas particle-phase dimers (C₁₉H₃₀O₅) are observed to form during F-TD analysis via thermally induced condensation of synthesized pinene-derived alcohols and diacids. The complementary F-TD/CIMS + UPLC/ESI-MS method offers previously inaccessible insight into the molecular composition and thermal desorption behavior of SOA that both clarifies and expands on analysis via traditional F-TD techniques.

Additional Information

© 2020 American Chemical Society. Received: March 21, 2020; Revised: June 11, 2020; Accepted: June 12, 2020; Published: June 12, 2020. We appreciate insightful discussions with John D. Crounse and Lu Xu. We acknowledge generous support from Dwight and Christine Landis. UPLC/(−)ESI-Q-TOF-MS was performed in the Caltech Environmental Analysis Center (EAC). The EAC is supported by the Linde Center and Beckman Institute at Caltech. The authors declare no competing financial interest.

Attached Files

Supplemental Material - es0c01779_si_001.pdf


Files (1.8 MB)
Name Size Download all
1.8 MB Preview Download

Additional details

August 19, 2023
October 20, 2023