H87.0.0X.6C-01
Operating manual G 7500 Series
page 13 of 34
6.1.3 Further information
pH electrode is a wear part. If the signal is very slow or the required values are no
longer observed after careful cleaning and possible regeneration, the electrode must
be replaced. When using the electrodes, be aware that various substances in
aqueous solutions can corrode glass and that chemicals can produce a chemical
reaction with the KCl solution in the electrode, which can result in blockage of the
diaphragm.
Examples:
In solutions that contain proteins, such as for measurements in medical and
biological applications, KCl can cause denaturation of the protein.
Coagulated paints
Solutions that contain high concentrations of silver ions
Substances that accumulate on the glass membrane or the diaphragm affect the
measurement and must be removed regularly. This can be achieved for example
with automatic cleaning systems.
6.1.4 Choosing a pH electrode
GE 100 BNC is a universal electrode with two ceramic diaphragms and liquid
GE 101 BNC is preferably used for small sample amounts. It comprises a glass
electrode with two ceramic diaphragms and liquid electrolyte.
GE 104 BNC is preferably used for measurements in low-ionic media, such as
rainwater, aquarium water and deionised water.
GE 114 WD is a universally applicable, durable and low-maintenance gel
electrode with Pellon diaphragm. It can be used for measurements in drinking
water, swimming pools, aquaria and slightly contaminated waste water.
GE 117 BNC is a temperature-compensated gel electrode with two ceramic
diaphragms and PH 13.5 cable screw coupling.
GE 120 BNC is an insertion electrode and is preferably used for measurements
in cheese, fruit and meat. For measurements in products containing proteins,
the electrode must be cleaned with a special cleaner. For this purpose, we
recommend the GRL 100 pepsin cleaning solution.
GE 125 BNC is a waterproof, universally applicable, durable and low-
maintenance gel electrode with ceramic diaphragm. It can be immersed above
the shaft for an extended time.
GE 151 BNC is a glass electrode and is preferably used in galvanic
applications for paints and lacquers.
GE 173 BNC is an alkaline-resistant glass electrode with ground diaphragm
and gel electrolyte for chemical and waste water applications.
