Voltammetric methods are based on measurements made using an
electrochernical cell in which electrolysis is occurring. Voltammetry,
sometimes also called amperometry, involves the use of a potential applied
between two electrodes (the working electrode and the reference electrode) to
cause oxidation or reduction of an electroactive analyte. The loss or gain of
electrons at an electrode surface causes current to flow, and the size of the
current (usually measured in mA or µ
A) is directly proportional to the
concentration of the electroactive analyte. The materials used for the working
electrode must be good conductors and electrochernically inert, so that they
simply transfer electrons to and from species in solution. Suitable materials
include Pt, Au, Hg and glassy carbon.
Two widely used devices that operate on the voltammetric principle are the
oxygen electrode and the glucose electrode. These are sometimes referred to
as amperometric sensors.