Patented three-chambers system with Iodine reservoir in the iodine / iodide reference electrode. The component determining the potential, i. e. the Iodine, is continuously being resupplied. The first chamber contains a supply which is used to fresh up the reference electrolyte and the reference system of the second chamber with iodine in order to maintain the necessary I3-
concentration and thereby a stable reference potential. The electrolyte link between the second and the third chamber containing the exchangeable bridge electrolyte is provided by an interior diaphragm, allowing only a minimal diffusion. The bridge electrolyte also provides the contact with the sample via the diaphragm. The reference system is based on the following reaction:
+ 2 e-
<=> 3 I-
The ORP is thereby described by the Nernstian equation:
EH = E° + RT / zF * ln ([I3-
] / [I-
whereby E° = 0.536 V, R = 8.314472 I / (K * mol),
T in K, z = 2 and F = 96485.34 C / mol.
The stability of the reference system potential even at changing temperatures is the key to the IoLine electrodesá superior response speed and measurement stability and, additionally, higher accuracy compared to conventional Ag / AgCl electrodes. A platinum diaphragm which is inherent to the MF version of the electrodes ensures a remarkable constancy and reproducible measuring. The diaphragm contains twisted platinum wires being fused into the glass shaft of the electrode.
|Reference system:||iodine / iodide|
|Zero point:||pH = 7.00 ± 0.25|
|pH range:||0 to 14|
|Temperature range:||- 5 to + 100 °C|
|Shape of membrane:||sphere|