H87.0.0X.6C-01
Operating manual G 7500 Series
page 14 of 34
6.1.5 Service life
The service life of electrodes is normally at least 8 to 10 months. When
cared for properly, this can usually increase to more than 2 years. The
actual life will vary depending on the particular application.
6.1.6 Care and maintenance
The GAK 1400 working and calibration set includes all necessary
products for calibration, care and maintenance of the electrode.
Normal cleaning takes place with the GRL 100 pepsin cleaning
solution into which the electrode is immersed for 5 minutes before
being rinsed off with clean water.
Crystallization of the 3 mol/l KCL solution is unavoidable. Crystallized
potassium chloride on the protective cap and shaft can easily be
removed with a fingernail or cloth and is therefore does not constitute
a defect or cause for complaint.
Dirty electrodes must be cleaned. The suitable cleaning agents for the pH glass
membrane are listed in the table below.
Impurities
Cleaners
General residue
Mild detergent
Inorganic coatings
1 mol/l HCl solution or GRL 100 pepsin
cleaning solution
Metal compounds
1 mol/l HCl solution or GRL 100 pepsin
cleaning solution
Oil and grease
Special cleaner or solvent
Biological coatings with protein
1% pepsin enzyme in 0.1 molar GRL 100
HCl solution
Biological coatings with protein
Acetone
Extremely resistant residues
Hydrogen peroxide or sodium hypochloride
The material of the pH probe must always be protected. Plastic shafts must not be
cleaned in solvents, etc. If in doubt, contact the manufacturer to inquire about suitable
cleaners for the existing electrode. This is also important in the case of aggressive
substances or other substances that are not primarily water-based!
