On the velocity sensitivity (stirring effect) of polarographic oxygen microelectrodes
Gust, G.; Booij, K.; Helder, W.; Sundby, B. (1987). On the velocity sensitivity (stirring effect) of polarographic oxygen microelectrodes. Neth. J. Sea Res. 21(4): 255-263
In: Netherlands Journal of Sea Research. Netherlands Institute for Sea Research (NIOZ): Groningen; Den Burg. ISSN 0077-7579; e-ISSN 1873-1406, meer
|  |
| Auteurs | | Top |
- Gust, G.
- Booij, K.
- Helder, W.
- Sundby, B.
|
|
|
| Abstract |
The current-output by oxygen microelectrodes in water decreases substantially at low flow velocities because of the increased importance of the mass-transfer resistance that is posed by the boundary layer surrounding the probe. The magnitude of this velocity effect increases with increasing sensitivity of the probe. Thus, depending on the probe, 10 to 15% reductions in current output were observed between free flow and zero flow at the same oxygen concentration. Before using microelectrodes to measure oxygen in sediment pore waters, they must be tested for the magnitude of the velocity effect and, if necessary, calibrated in zero-flow water. Caution is advised in interpreting data obtained with oxygen microelectrodes in the low velocity region near solid-fluid interfaces unless both the velocity gradient in this region and the velocity effect on the elctrode are known. |
|
