What does the term resistance mean in relation to pH electrodes, and why is it important?
This is a measure of the electrical resistance of the measuring electrode of a pH electrode. It is influenced by the chemical composition of the glass, its thickness and shape. The resistance of pH membrane glass is important as it increases with decreasing temperature. A change in resistance leads to a change in electrode response, in particular the higher the resistance of the membrane the slower the electrode response is. This can result in an electrode not being useable at a particular temperature. For example, electrodes designed for low alkaline error at high temperatures are generally of higher than normal resistance and should not be used at all at low temperatures. For this reason manufacturers specify temperature ranges in which their electrodes can be used with confidence.
