Polarography

3) very easy cleaning of the electrode surface by making a new drop of mercury from a large Hg pool connected by a glass capillary.

Polarography played a major role as an experimental tool in the advancement of both Analytical Chemistry and Electrochemistry until the 1990s (see figure below), when it was supplanted by other methods that did not require the use of mercury.

In its most simple form polarography can be used to determine concentrations of electroactive species in liquids by measuring their mass-transport limiting currents.

As a consequence, the initial current is dominated by capacitive effects as charging of the rapidly increasing interface occurs.

Unfortunately, this process is complicated by the continuously changing potential that is applied to the working electrode (the Hg drop) throughout the experiment.

The first major improvement was obtained by measuring the current only at the end of each drop lifetime (tast polarography).

This technique and especially the differential pulse anodic stripping voltammetry (DPASV) method can be used for environmental analysis, and especially for marine study for the characterisation of organic matter and metals interactions.