Preferred Label : gas sensing electrode;
IUPAC definition : A sensor composed of an indicator and a reference electrode in contact with a thin
film of solution which is separated from the bulk of the sample solution by a gas-permeable
membrane or an air gap. This intermediate solution interacts with the gaseous species
(penetrated through the membrane or an air gap) in such a way as to produce a change
in a measured constituent (e.g. the H sup class plus /sup activity) of the intermediate
solution. This change is then sensed by the ion-selective electrode and is related
to the partial pressure of the gaseous species in the sample. [Note: In electrochemical
literature the term gas electrode is used for the classical, redox-equilibrium-based
gas electrodes as well, such as the hydrogen or the chlorine gas electrodes (Pt (s)
H sub 2 /sub (g) H sup class plus /sup (aq) or Pt (s) Cl sub 2 /sub (g)
Cl sup class minus /sup (aq)]. These electrodes respond both to the partial pressure
of the gas (H sub 2 /sub or Cl sub 2 /sub ) and to the ionic activities (H sup class
plus /sup or Cl sup class minus /sup ). The Clark oxygen electrode fits under
this classification although, in contrast to other gas sensors, it is an amperometric
and not a potentiometric device.;
Origin ID : G02590;
See also
A sensor composed of an indicator and a reference electrode in contact with a thin
film of solution which is separated from the bulk of the sample solution by a gas-permeable
membrane or an air gap. This intermediate solution interacts with the gaseous species
(penetrated through the membrane or an air gap) in such a way as to produce a change
in a measured constituent (e.g. the H sup class plus /sup activity) of the intermediate
solution. This change is then sensed by the ion-selective electrode and is related
to the partial pressure of the gaseous species in the sample. [Note: In electrochemical
literature the term gas electrode is used for the classical, redox-equilibrium-based
gas electrodes as well, such as the hydrogen or the chlorine gas electrodes (Pt (s)
H sub 2 /sub (g) H sup class plus /sup (aq) or Pt (s) Cl sub 2 /sub (g)
Cl sup class minus /sup (aq)]. These electrodes respond both to the partial pressure
of the gas (H sub 2 /sub or Cl sub 2 /sub ) and to the ionic activities (H sup class
plus /sup or Cl sup class minus /sup ). The Clark oxygen electrode fits under
this classification although, in contrast to other gas sensors, it is an amperometric
and not a potentiometric device.
