What is the Difference Between Polarography and Voltammetry?

Polarography and voltammetry are both electroanalytical methods used to analyze unknown substances in solution that are electroactive, or capable of generating an electric current when an electric potential is applied to them. Despite their similarities, there are key differences between the two techniques:

1. Types of electrodes used: The main difference between polarography and voltammetry lies in the polarization electrode. Polarography uses a dropping mercury electrode (DME) or other liquid electrode whose surface can be renewed periodically, while voltammetry uses a liquid or solid electrode whose surface is still.
2. Subclass relationship: Polarography is considered a subclass of voltammetry.
3. Sensitivity: Polarography is known for its high sensitivity and ability to detect low concentrations, making it more suitable for the analysis of trace amounts of analytes in solution.
4. Applications: Polarography is best suited for the analysis of electrochemically active species, while voltammetry can be used for both electroactive and non-electroactive species.

In summary, the key difference between polarography and voltammetry is the type of polarization electrode used. Polarography uses a liquid electrode with a renewable surface, while voltammetry uses a still surface electrode. Polarography is a more sensitive technique, making it better suited for the analysis of trace amounts of analytes in solution, whereas voltammetry can be used for a broader range of species.

Comparative Table: Polarography vs Voltammetry

Here is a table comparing the differences between polarography and voltammetry:

Polarography is a subclass of voltammetry, and the key difference between the two is the type of electrode used and the specific techniques employed.