Voltammetric Techniques: Linear-Scan (E vs Time)

In polarography, a classical voltammetric technique, a linear potential sweep is applied to a dropping mercury electrode or DME, and the resulting current is measured.

In DME, a small mercury droplet forms at the capillary tip and continuously drops, creating a new electrode surface for each measurement.

The resulting current-potential plot, known as a polarogram, provides information about half-wave potential, residual current, limiting current, and diffusion current. The diffusion current is directly proportional to the analyte concentration in the solution.

Polarography is utilized to analyze metal ions, inorganic anions, and organic compounds that contain functional groups capable of easy reduction or oxidation.

On the other hand, hydrodynamic voltammetry measures current as a function of the same potential profile as polarography but applied to a solid working electrode.

The resultant voltammograms are similar to polarograms, without current oscillations due to the formation of mercury drops.