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| Titel |
A chemical ionization mass spectrometer for continuous underway shipboard analysis of dimethylsulfide in near-surface seawater |
| VerfasserIn |
E. S. Saltzman, W. J. Bruyn, M. J. Lawler, C. A. Marandino, C. A. McCormick |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1812-0784
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| Digitales Dokument |
URL |
| Erschienen |
In: Ocean Science ; 5, no. 4 ; Nr. 5, no. 4 (2009-11-06), S.537-546 |
| Datensatznummer |
250002730
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| Publikation (Nr.) |
 copernicus.org/os-5-537-2009.pdf |
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| Zusammenfassung |
| A compact, low-cost atmospheric pressure, chemical ionization mass
spectrometer ("mini-CIMS") has been developed for continuous underway
shipboard measurements of dimethylsulfide (DMS) in seawater. The instrument
was used to analyze DMS in air equilibrated with flowing seawater across a
porous Teflon membrane equilibrator. The equilibrated gas stream was diluted
with air containing an isotopically-labeled internal standard. DMS is
ionized at atmospheric pressure via proton transfer from water vapor, then
declustered, mass filtered via quadrupole mass spectrometry, and detected
with an electron multiplier. The instrument described here is based on a
low-cost residual gas analyzer (Stanford Research Systems), which has been
modified for use as a chemical ionization mass spectrometer. The mini-CIMS
has a gas phase detection limit of 220 ppt DMS for a 1 min averaging
time, which is roughly equivalent to a seawater DMS concentration of 0.1 nM
DMS at 20°C. The mini-CIMS has the sensitivity, selectivity, and time
response required for underway measurements of surface ocean DMS over the
full range of oceanographic conditions. The simple, robust design and
relatively low cost of the instrument are intended to facilitate use in
process studies and surveys, with potential for long-term deployment on
research vessels, ships of opportunity, and large buoys. |
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