Principle Of The Design Of An Oxygen Electrode - Mettler Toledo InPro6900 Bedienungsanleitung

InPro 6900 Series O
10.2 Principle of the design of an
oxygen electrode
There are two main types of oxygen electrodes:
– Electrodes without membrane
– Electrodes with gas-permeable membrane
(Clark Principle)
The membrane electrode according to Clark is today
most widely used. As compared to the electrode with-
out membrane it possesses the following advantages:
– Oxygen measurement in gases and solutions
– No mutual contamination of electrode and solution
– No or little dependency on flow
In the case of the Clark electrode, geometrical config-
uration is very important. In particular, the thickness of
the electrolyte film between the cathode and the mem-
brane must be within narrow tolerances so as to ensure
good linearity and a low zero current (current in a ni-
trogen atmosphere). The figure above exemplifies the
principle of the design of a Clark-type oxygen elec-
trode.
© 12 / 15 Mettler-Toledo GmbH
Printed in Switzerland
Sensor 12 mm
2
measuring solution
A
31
polarization
voltage
anode
electrolyte
insulator
cathode
membrane
InPro 6900
52 201 029