pH 7110 - Fagerberg

Glossary pH 711012 Glossary12.1 pH/ORPSpecialisttermDescriptionAsymmetryDiaphragmElectromotiveforce of anelectrodeORPpH valueSlopeZero pointsee zero pointThe junction is a porous body in the housing wall of referenceelectrodes or electrolyte bridges. It arranges theelectrical contact between two solutions and makes theelectrolyte exchange more difficult. The expression, junction,is also used for ground or junction-less transitions.The electromotive force U of the combination electrode isthe measurable electromotive force of an electrode in asolution. It equals the sum of all the galvanic voltages ofthe electrode. Its dependency on the pH results in theelectrode function, which is characterized by the parameters,slope and zero point.The ORP is caused by oxidizing or reducing substancesdissolved in water if these substances become effectiveon an electrode surface (e. g. a gold or platinum surface).The pH value is a measure of the acidic or basic effect ofan aqueous solution. It corresponds to the negativedecadic logarithm of the molal hydrogen ions activitydivided by the unit of the molality. The practical pH value isthe value of a pH measurement.The slope of a linear calibration function.The zero point of a pH combination electrode is the pHvalue at which the electromotive force of the pH combinationelectrode at a specified temperature is zero. Normally,this is at 25 °C.46 ba75925e01 07/2011