Dissolved oxygen electrode

on the basis of

Polarography

By:

Abhishek R. Indurkar

17PBT202

Polarography

It is an electromechanical technique of analyzing

solutions that measures the current flowing between

two electrodes in the solution as well as the gradually

increasing applied voltage to determine respectively

the concentration of a solute and its nature.

It was invented in 1922 by Czech chemist Jaroslav

Heyrovský, for which he won the Nobel prize in 1959.

Clark Cell

In the polarographic (or Clark) cell shown in a

cathode of a noble metal is made negative by 0.6 to

0.8 Volts with respect to a suitable reference anode

so that any oxygen dissolved in the liquid is reduced

at the surface of the noble metal cathode.

Reaction at cathode: O2 +2H2O+4e- →4OH-

Reaction at anode: 4Ag + 4Cl- → 4AgCl + 4e-

Thank You