What is a polarographic electrode?
Polarography is a type of voltammetry where the working electrode is a dropping mercury electrode (DME) or a static mercury drop electrode (SMDE), which are useful for their wide cathodic ranges and renewable surfaces.
What is the main source of error in the oxygen electrode?
Well-known cause of frequent failures of closed oxygen sensors is the appearance of gas bubbles in the electrolyte. The problem is traditionally associated with insufficient sealing of the sensor that is not always true.
Which detector is used in polarographic method?
Polarography using the dropping mercury electrode has some advantages as a liquid chromatography (LC) detecting system.
What is polarographic dissolved oxygen sensor?
Polarographic dissolved oxygen sensors are membrane based and use an electrochemical technology. Oxygen diffuses through the membrane and is reduced at a cathode that is held at a defined potential. The measured reduction current is proportional to the partial pressure of oxygen in the media.
What is the function of the Clark electrode?
The Clark electrode is an electrode that measures ambient oxygen concentration in a liquid using a catalytic platinum surface according to the net reaction: O 2 + 4 e − + 4 H + → 2 H 2 O It improves on a bare platinum electrode by use of a membrane to reduce fouling and metal plating onto the platinum.
How did Clark limit the diffusion of oxygen?
Increasing the voltage applied (between the Pt electrode and a second Ag electrode) will increase the rate of electrocatalysis. Clark affixed an oxygen permselective membrane over the Pt electrode. This limits the diffusion rate of oxygen to the Pt electrode.
When did Clark and Lyons invent the oxygen electrode?
The Clark oxygen electrode laid the basis for the first glucose biosensor (in fact the first biosensor of any type), invented by Clark and Lyons in 1962. This sensor used a single Clark oxygen electrode coupled with a counter-electrode. As with the Clark electrode, a permselective membrane covers the Pt electrode.
What kind of anode is the Clark anode?
This silver/ silver chloride (Ag/AgCl) anode provides electrons for the cathode reaction. The Clark (pO2) electrode measures oxygen tension amperometrically.