Frequently Asked Question

## Instrumentation of Polarography
1. Polarographic Cell:
A three-electrode system is used, consisting of:

Working Electrode: A dropping mercury electrode (DME) or a static mercury drop electrode (SMDE) is typically employed. The DME provides a constantly renewed surface, minimizing surface contamination.

Reference Electrode: A saturated calomel electrode (SCE) or a silver/silver chloride electrode (Ag/AgCl) provides a stable reference potential.

Auxiliary Electrode: A platinum wire or a graphite rod serves as the counter electrode to complete the circuit.
2. Potentiostat:
A potentiostat controls the potential difference between the working electrode and the reference electrode, applying a linear voltage ramp.
3. Current Measuring Device:
An ammeter or a sensitive galvanometer measures the current flowing between the working electrode and the auxiliary electrode.
4. Recorder or Data Acquisition System:
The current is recorded as a function of the applied potential, generating a polarogram.
5. Dropping Mercury Electrode (DME):
The DME consists of a fine capillary tube through which mercury flows. The mercury drops at a constant rate, creating a constantly renewed surface. This minimizes surface contamination and provides a reproducible electrode.
6. Static Mercury Drop Electrode (SMDE):
The SMDE is a modified version of the DME that provides a stable mercury drop for a longer period, enhancing the sensitivity of the measurements.
7. Gas Purge System:
A gas purging system, typically using nitrogen or argon, is used to remove dissolved oxygen from the solution. Oxygen can interfere with the polarographic measurements.