Record Details
High-frequency measurement of partial pressure and total concentration of carbon dioxide in seawater using microporous hydrophobic membrane contractors
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | High-frequency measurement of partial pressure and total concentration of carbon dioxide in seawater using microporous hydrophobic membrane contractors |
| Names |
Hales, Burke
(creator) Chipman, David (creator) Takahashi, Taro (creator) |
| Date Issued | 2004-11 (iso8601) |
| Abstract | To investigate CO₂ chemistry in ocean water with greater time-space resolutions, we developed measurement systems, which have state-of-the-art precision but an order of magnitude or better increase in the frequency of analysis, for carbon dioxide partial pressures (Pco₂) and total carbon dioxide concentrations (Tco₂) in seawater. The Pco₂ system was based on equilibration of a CO₂-free carrier gas stream with aqueous carbon dioxide in a flowing seawater sample stream using a commercially available membrane contactor unit normally employed in industrial applications followed by nondispersive infrared (NDIR) absorbance detection of the CO₂ in the exit carrier gas. The Tco₂ system was based on injection of a small-volume seawater sample loop (~1 mL) into an acid (0.1 N HCl) liquid carrier stream to convert all carbonate and bicarbonate ions to aqueous carbon dioxide; this acidified sample was then passed through a custom-made small-volume membrane contactor unit where the sample’s Pco₂ was determined by equilibration of a CO₂-free carrier gas followed by NDIR detection. Results from lab tests and a field experiment in the Ross Sea polynya, Antarctica, are presented. The Pco₂ system was determined to have a response time of about 3 s and precision of better than 1 μatm. The Tco₂ system had a maximum analysis rate of one sample per 36 s, and reproducibility was determined to be better than 0.2% for a period of hours. |
| Genre | Article |
| Identifier | Hales, B., Chipman, D., & Takahashi, T. (2004). High-frequency measurement of partial pressure and total concentration of carbon dioxide in seawater using microporous hydrophobic membrane contractors [Electronic version]. Limnology and Oceanography: Methods, 2, 356-364. |
