There are two fundamental amperometric
techniques for measuring DO— galvanic and polarographic.
Both probes use an electrode system where the
DO reacts with the cathode to produce a current.
If an external voltage is applied, the system
is called polarographic. YSI-556 – cap membranes
Polarographic probes have polarographic sensors with silver
anode surrounded by a
gold or platinum cathode. This type of probe is also called the “Clark
cell”.