pH measurements with separate electrodes require the use of a measurement electrode and a reference electrode. The latter will retain a constant, stable potential during the measurements.
- Calomel (Hg/Hg2Cl2)
reference electrode, usually called an SCE
(Saturated Calomel Electrode).
This comprises a glass tube in which a drop of mercury and mercury chloride (calomel) are placed in contact with a platinum wire. The reference element is filled with a saturated KCl solution (KCl 3 mol/L).
- Equipped with a porous ceramic junction which allows the reference electrolyte to "sweat" but prevents it from flowing freely.
- High stability over time and low temperature coefficient.
This is ideal for many applications except for those where the chloride ions might react with a compound present in the solution, as is the case with Ag+ ions with which the chloride ions form a precipitate, AgCl. In such cases, a mercurous sulphate reference electrode should be used.
The choice of the reference electrode depends above all on the experimental conditions for your measurements.
This reference electrode should be used with a measurement electrode (BV41A/H or XV41) for correct pH measurement.
- Various connection technologies are available for adaptation to all your instruments.
For further technical details, please read the sales brochure on the electrodes and/or contact us.