Hanna Instruments offers a wide variety of pH electrodes that are designed for many different applications. The type of glass used, body material, type of junction, type of reference and electrolyte used are just some of the design considerations.
The HI5413 uses a glass body, calomel references, PTFE sleeve junction and is refillable with 3.5M KCl.
The glass body is ideal for laboratory use. The glass is resistant to many harsh chemicals and is easily cleaned. The glass body also allow for a fast transfer of heat to the internal reference electrolyte. The mV generated by the reference cell is temperature dependent. The faster the equilibrium the steadier the reference potential.
PTFE Sleeve Junction
Conventional pH electrodes use ceramic junctions that clog quickly when used in samples with high amounts of particulates. When the junction is clogged, the electrode does not function. The use of a polytetrafluoroethylene (PTFE) sleeve junction prevents clogging of the junction and allows proper flow of the liquid electrolyte. As a result, pH electrodes with sleeve junctions stay fresh up to 20 times longer than conventional electrodes.
The HI5413 is a refillable reference electrode. Since it is a single junction calomel electrode the fill solution is the HI7082 3.5M KCl. This solution does not contain any silver as with single junction silver/silver chloride reference electrodes. The absence of silver will prevent any silver precipitate from forming at the junction surface and clogging it. Clogging of the junction will result in drifty and erratic readings.
4 mm Connector
The HI5413 uses a 4 mm banana connector. This type of connector is easily plugged into the reference input on suitable meters. Other type of connectors include BNC, DIN, screw type, T-type, and 3.5mm to name a few. These types of connectors tend to be proprietary for a particular type of meter and are not interchangeable.