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CH3041
GAS SENSING
ELECTRODES.h
Gas sensing electrodes.
• These devices contain a conventional pH
electrode surrounded by a membrane that
isolates the analyte to which the electrode
responds. CO2 gas sensing electrode
electrode surrounded by a membrane that
isolates the analyte to which the electrode
responds. CO2 gas sensing electrode
Teflon
membrane
0.1M KCl/buffer
0.1M KCl/buffer
V
Ag/AgCl
Electrolyte
Glass membrane
• CO2 diffuses
through a membrane
such as Teflon and enters the enclosed
KCl / weak HCO3- buffer chamber.
such as Teflon and enters the enclosed
KCl / weak HCO3- buffer chamber.
•The pH is lowered (H2CO3)
and the glass electrode
registers the new pH which
is converted to ppm CO2.
and the glass electrode
registers the new pH which
is converted to ppm CO2.
• Calibration is
needed.
