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  • New insights into atmospherically relevant reaction systems using direct analysis in real-time mass spectrometry (DART-MS)
Title: New insights into atmospherically relevant reaction systems using direct analysis in real-time mass spectrometry (DART-MS)
The application of direct analysis in real-time mass spectrometry (DART-MS), which is finding increasing use in atmospheric chemistry, to two different laboratory model systems for airborne particles is investigated: (1) submicron C3–C7 dicarboxylic acid (diacid) particles reacted with gas-phase trimethylamine (TMA) or butylamine (BA) and (2) secondary organic aerosol (SOA) particles from the ozonolysis of α-cedrene. The diacid particles exhibit a clear odd–even pattern in their chemical reactivity toward TMA and BA, with the odd-carbon diacid particles being substantially more reactive than even ones. The ratio of base to diacid in reacted particles, determined using known diacid–base mixtures, was compared to that measured by high-resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS), which vaporizes the whole particle. Results show that DART-MS probes  ∼  30 nm of the surface layer, consistent with other studies on different systems. For α-cedrene SOA particles, it is shown that varying the temperature of the particle stream as it enters the DART-MS ionization region can distinguish between specific components with the same molecular mass but different vapor pressures. These results demonstrate the utility of DART-MS for (1) examining reactivity of heterogeneous model systems for atmospheric particles and (2) probing components of SOA particles based on volatility.  more » « less
Award ID(s):
1207112 1443140 1404233 1337080 0923323
PAR ID:
10043185
Author(s) / Creator(s):
; ; ; ; ;
Date Published:
Journal Name:
Atmospheric Measurement Techniques
Volume:
10
Issue:
4
ISSN:
1867-8548
Page Range / eLocation ID:
1373 to 1386
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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