Double Junction Reference Electrode (Calomel)

A glass bodied reference electrode half-cell with a 12mm body and a Calomel Inner reference.

Double Junction reference electrodes have two separate chambers. The outer chamber is filled with 0.1 Molar Potassium Nitrate Solution. Standard calomel references slowly leak out Potassium Chloride into the samples during measurement. There are many applications where this is unacceptable e.g. Chloride ,Potassium, Nitrate and Silver analysis.

Separate reference electrodes are superior to the reference half cells found in combination electrodes. They have a larger reservoir of filling solution and therefore a faster flow rate of electrolyte through the junction. This provides faster response and greater stability. The EDT Double Junction Reference Electrodes have several advantages over combination electrode alternatives. Firstly they provide a longer lifetime as the internal reference solution is never in contact with the sample thereby avoiding contamination. In addition when combination electrodes fail due to the sensor failure the reference is immediately rendered useless.

If the solution provided is not suitable for the application the outer chamber can be filled with any inert salt solution that does not affect the sample. Simply remove with a pipette or syringe and refill.

Using Half Cells allows the operator to replace the faulty unit and retain the working unit. Double junction reference electrodes are typically used for ISE analysis where the leached electrolyte must not interfere with the ISE being used. They are also particularly useful for pH analysis of products that must not have KCl or a strong electrolyte contaminating the sample.

The inner junction is filled with Saturated KCl (Potassium Chloride). The outer can be filled with the electrolyte of your choosing (see filling solutions) to suit the application. This EDT E8094 electrode comes filled with 0.1 Molar Potassium Nitrate solution as standard and comes with a 4mm connector and is compatible with all types of pH ISE and REDOX half-cells.