Maintenance; Meter Maintenance; Electrode Maintenance - Mettler Toledo EL20 Bedienungsanleitung

Maintenance

5. Maintenance
5.1

Meter maintenance

Never unscrew the two halves of the housing!
The Education Line instruments do not require any maintenance other than occasional wipe with a damp
cloth and the replacement of depleted batteries (EL2).
The housing is made of acrylonitrile butadiene styrene/polycarbonate (ABS/PC). This material is attacked
by some organic solvents, such as toluene, xylene and methyl ethyl ketone (MEK). Any spillage should
be immediately wiped off.
5.2

Electrode maintenance

Make sure the electrode is filled with electrolyte solution if applicable.
For maximum accuracy, any filling solution that may have "crept" and encrusted the outside of the
electrode should be removed with deionized water.
Always store the electrode according to the manufacturer's instructions and do not allow it to dry out.
If the electrode slope falls rapidly, or if the response becomes sluggish, the following procedures may
help. Try one of the following, depending the samples usually measured.
. For fat or oil build-up, degrease the membrane with cotton wool soaked in either acetone or a soap
solution.
2. If the sensor membrane has dried out, soak the tip of the electrode in 0. M HCl overnight.
3. If a protein build-up has occurred in the diaphragm, remove deposits by soaking the electrode in an
HCl /pepsin solution (5340068).
4. If a silver sulfide contamination has occurred, remove deposits by soaking the electrode in a solution
of thiourea (5340070).
After treatment a new calibration should be performed.
Note:
Cleaning and filling solutions should be handled with the same care as that given to toxic or corrosive
substances.
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METTLER TOLEDO Education Line pH meter
12.03.2007 15:08:48