| quinhydrone electrode | One of several oxidation-reduction electrode's in which the ratio of the two forms (quinone-quinhydrone), determined by the hydrogen ion concentration, sets up a potential that can be measured and converted to a pH value (fails above pH 8). (05 Mar 2000) |
|---|---|
| ion selective electrode | An electrode half cell, with a semi permeable membrane that is permeable only to a single ion. The electrical potential measured between this and a reference half cell (e.g. A calomel electrode) is thus the Nernst potential for the ion. Given that the solution filling the ion selective electrode is known, the activity (rather than concentration) of the ion in the unknown solution can be measured. Commercial ion selective electrodes frequently use a hydrophobic membrane containing an ionophore, such as valinomycin (for potassium) or monensin (for sodium). A pH electrode is made with a thin membrane of pH sensitive (i.e. Proton permeable) glass. (18 Nov 1997) |
| oxidation-reduction electrode | An electrode capable of measuring oxidation-reduction potential. See: quinhydrone electrode. Synonym: redox electrode. (05 Mar 2000) |
| oxygen electrode | A sensitive method to detect oxygen consumption, involves a PTFE (Teflon) membrane. (18 Nov 1997) |
| therapeutic electrode | A small electrode whose exciting effect is used to stimulate or record potentials from a localised area. Synonym: exciting electrode, localizing electrode, therapeutic electrode. (05 Mar 2000) |
| enzyme electrode | A type of biosensor. An enzyme is immobilised on the surface of an electrode, and when the enzyme catalyses its reaction, electrons are transferred from the reactant to the electrode, and a current is generated, which can then be measured. (14 Nov 1997) |
| exciting electrode | A small electrode whose exciting effect is used to stimulate or record potentials from a localised area. Synonym: exciting electrode, localizing electrode, therapeutic electrode. (05 Mar 2000) |
| exploring electrode | An electrode placed on or near an excitable tissue; in unipolar electrocardiography, the electrode is placed on the chest in the region of the heart and paired with an indifferent electrode. (05 Mar 2000) |
| localizing electrode | A small electrode whose exciting effect is used to stimulate or record potentials from a localised area. Synonym: exciting electrode, localizing electrode, therapeutic electrode. (05 Mar 2000) |