The electrolytic chloridation unit Auto Chloridizer 863 provides a simple means for the chloridation of Ag/AgCl electrodes. It covers the surface of the silver electrode with an AgCl film insoluble in water. Unlike a purely chemical procedure, electrolytic chloridation does not involve the use of substances endangering the environment. It is normal practice to work with physiological saline solution (NaCl) as the electrolyte.
The electrolytic chloridation method also offers excellent reproducibility of the AgCl film at constant current density and chloridation time. The auto chloridizer operates with an electronically controlled constant-current source with current monitoring and error indication through an LED and error beep. During the chloridation of a single Ag/AgCl electrode the unit is operated manually through the start/stop key.
For routine production of several identical electrodes, such as Ag/AgCl wires for glass microelectrodes, the unit offers a simple programming feature for the chloridation period in the repeat mode. First the learning mode is initiated by pressing the repeat key (for longer than 1 second) and then an electrode is produced manually using the start/stop key. All further electrodes are then prepared automatically according to the manual setting by pressing the repeat key. The end of the chloridation process is indicated by a beep and the current source is automatically switched off.
The counter electrode (cathode) used is a carbon-glass ceramic crucible. This material has a very high electrical conductivity, is very largely inert physiologically, and resistant to oxidation and corrosion. There is therefore no contamination of the AgCl film through free metal ions, as is the case when using stainless steel as a cathode for example.