Antec Scientific ROXY Exceed, User Manual, Page: 54 / 126

54 211_0010 - ROXY Exceed user manual - rev 04
Essentially, for the oxidation or reduction reaction it would be sufficient to
use only two electrodes. However, the three-electrode configuration has
several advantages over a two-electrode configuration. If the working po-
tential would be applied only over an AUX versus the WE (without REF),
the working potential would continuously change due to polarization effects
at the electrodes, resulting in highly unstable working conditions.
If the working potential would be applied only over the REF versus the WE
(without AUX), the working potential would be very well defined. However,
the potential of a REF is only well defined if the current drawn is extremely
low (pico-amperes) resulting in a very limited dynamic range.
A three-electrode configuration, combines the best of both electrodes. The
REF stabilizes the working potential and the AUX can supply high cur-
rents. This results in the tremendous dynamic range of a three-electrode
system.
For some ROXY applications like the reduction of disulfide bridges in pro-
teins and peptides a two-electrode configuration is used for efficient reduc-
tion. See figure below.
Fig. 11. Schematic representation of an electrochemical cell and potenti-
ostat electronics operating with a two-electrode configuration.