Challenges associated with the sampling and analysis of organosulfur compounds in air using real-time PTR-ToF-MS and offline GC-FID
Organosulfur compounds (OSCs) are naturally emitted via various processes involving phytoplankton and algae in marine regions, from animal metabolism, and from biomass decomposition inland. These compounds are malodorant and reactive. Their oxidation to methanesulfonic and sulfuric acids leads to th...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-03-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | http://www.atmos-meas-tech.net/9/1325/2016/amt-9-1325-2016.pdf |
| Summary: | Organosulfur compounds (OSCs) are naturally emitted via various processes
involving phytoplankton and algae in marine regions, from animal metabolism,
and from biomass decomposition inland. These compounds are malodorant and
reactive. Their oxidation to methanesulfonic and sulfuric acids leads to the
formation and growth of atmospheric particles, which are known to influence
clouds and climate, atmospheric chemical processes. In addition, particles
in air have been linked to negative impacts on visibility and human health.
Accurate measurements of the OSC precursors are thus essential to reduce
uncertainties in their sources and contributions to particle formation in
air. Two different approaches, proton-transfer reaction time-of-flight mass
spectrometry (PTR-ToF-MS) and canister sampling coupled to gas chromatography with flame ionization detector (GC-FID), are
compared for both laboratory standards (dimethyl sulfide, DMS; dimethyl
disulfide, DMDS; dimethyl trisulfide, DMTS; and methanethiol, MTO) and for
a complex sample. Results show that both techniques produce accurate
quantification of DMS. While PTR-ToF-MS provides real-time measurements of
all four OSCs individually, significant fragmentation of DMDS and DMTS
occurs, which can complicate their identification in complex mixtures.
Canister sampling coupled with GC-FID provides excellent sensitivity for
DMS, DMDS, and DMTS. However, MTO was observed to react on metal surfaces to
produce DMDS and, in the presence of hydrogen sulfide, even DMTS. Avoiding
metal in sampling systems seems to be necessary for measuring all but
dimethyl sulfide in air. |
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| ISSN: | 1867-1381 1867-8548 |