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CH3041
OXYGEN ELECTRODE
Dissolved Oxygen
“Electrodes”. These are actually oxygen sensors (probes) as the device contains two
electrodes.
• Current
is measured across the electrodes making this an amperometric technique.
Clark electrode: A Pt
cathode is held at -0.6V
relative to Ag|AgCl. The semipermeable
PTFE membrane allows oxygen to diffuse across in seconds.
relative to Ag|AgCl. The semipermeable
PTFE membrane allows oxygen to diffuse across in seconds.
Cathode: O2 + 2H+ + 2e- ® H2O2
Anode: 2Ag + 2Cl- ® 2AgCl + 2e-
• The current that
flows is
proportional to the [O2].
proportional to the [O2].
• IDL 0.2ppm
Pt cathode
Ag|AgCl anode
Teflon
membrane
membrane
electrolyte
readout
