The hanging mercury drop electrode (HMDE) is a
useful device for laboratory experiments in various fields as,
for example, trace analysis by stripping voltammetry (1–4),
linear scan voltammetry (5, 6 ), or the study of complex equilibria
in aqueous solutions (7). Despite the advent of various
kinds of solid or modified electrodes, the HMDE remains a
standard tool in analytical voltammetry (8). Galus reviewed
mercury electrodes, including the HMDE (9). However, the
high price of commercially available models could restrict the
use of the HMDE in the teaching laboratory. On the other
hand, the construction of one of the various models described
in the literature may require a high degree of mechanical and
electrical expertise. The model presented here is very simple
and can be built using only several inexpensive components,
most of them available from disabled equipment. Only moderate
mechanical and electrical skills are required, and average
glass blowing expertise is needed to construct the glass
parts of the device.