User manual

Z03.0.0X.6C-02 page 3 of 4
General maintenance and measuring instructions for pH-combination-electrodes
This pH-electrode has been tested and has been subordinated strict quality controls in all manufacturing-steps
1. To keep the optimum efficiency and accuracy for a long time take care of the following points:
1.1. Remove the storing protection-cap form the pH-glass-diaphragm and clean the glass-rod and the diaphragm
with distilled water. After that dry the diaphragm and the glass rod with a soft paper towel.
1.2. Important! The pH-glass-diaphragm has to be kept wet. When not in use the electrode must be stored in 3
mole/l KCl-dilution. (except GE 103 – here 1 mol/l KNO
3
). Should the pH-glass-diaphragm be dried out, the ef-
ficiency and the responsiveness are affected. To continuously moistening the electrode store it in 3 mol/l KCl-
dilution for 24 hours. (except GE 103)
A longer storage of a single-rod-electrode or a reference-electrode in destined water will deplete them of KCl.
Please refill KCl-electrolyte (saturated or 3 mole) in time (except GE 103)
1.3 Do not touch the glass-diaphragm! Damages on the surface and attrition affect the efficiency negatively.
1.4 Before using perform a visual check of the pH-electrode. Should there be air-bubbles in the pH-glass-
diaphragm or the outer reference-electrode you can get them out by shaking the electrode downward (like
handling a quicksilver-fibre-thermometer)
1.5 Take care that the side diaphragm contacts the media you want to measure.
Minimum depth for GE 100 e.g. 20 mm, maximum 50 mm
1.6 Keep cable and plug of the electrode always clean and dry. When not, the electric insulation will be lost,
through this measuring errors may occur.
1.7 The electrode has to be stored in dry rooms at temperatures between 10°C to 30°C. Below –5°C the electrode
may be damaged because the electrolyte may freeze.
2. care and maintenance
2.1 check the liquid level of the reference-electrode regularly and refill it with 3 mole KCl with the help of an
injection or a pipette. (except GE 107, GE 108, GE 109 an GE 117)
2.2 Crystallisation of the 3 mole/l KCl (3 mole KCl) is inevitable! Crystallised KCl on the protection-cap and the
breech-collar can be removed with fingernails or a paper towel. This is no defect or a reason for reclamation.
2.3 Contaminated electrodes have to be cleaned. The suitable cleaning agents for the pH-glass-diaphragm are
given in the table below:
contamination cleaning-agent
general deposits mild washing-agent
inorganic coatings common fluids for glass cleaning
metallic compounds 1 mole/l HCl-dilution
oil, fat special cleaning agents or solvent
biological coatings with protein pepsin-enzyme in 0,1 molar HCl-dilution (GRL100)
resin-lignin acetone
extreme resistant deposits hydrogen peroxide, sodium hypochloride
The distinct materials of the electrode have to be considered when choosing the cleaning agent.
E.g. electrodes with plastics shaft must not be cleaned with solvents. In case of doubt please contact the
manufacturer for further advice.
The same has to be considered when using aggressive or other, non water based agents!