Maintenance And Care; Cleaning The Instrument; Maintenance Of Electrodes - Mettler Toledo SevenExcellence Manual De Usuario

6 Maintenance and Care

Do not open the housing of the instrument; it does not contain any parts that can be maintained, repaired or
replaced by the user. If you experience problems with your instrument, contact your authorized METTLER TOLEDO
dealer or service representative.

6.1 Cleaning the Instrument

NOTICE
Danger of damage to the instrument due to inappropriate cleaning agents!
The housing is made of acrylonitrile butadiene styrene/polycarbonate (ABS/PC). This material is
sensitive to some organic solvents, such as toluene, xylene and methyl ethyl ketone (MEK). If
liquids enter the housing they can damage the instrument.
1 Use only water and a mild detergent to clean the housing.
2 Wipe off any spills immediately.
3 The instrument is IP54 splash water proof: Do not immerse the instrument in liquid.
§
The instrument is turned off and disconnected from the electrical outlet.
− Clean the housing of the instrument using a cloth dampened with water and a mild detergent.

6.2 Maintenance of electrodes

The instrument monitors the condition of the attached pH electrodes.
Slope: 95-105%
and offset: ± (0-20) mV
Electrode is in good condition
When cleaning, always follow the instructions in the manual of the electrodes used. Make sure the pH electrode
is always kept filled with the appropriate filling solution. 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 on your sample.
Problem
Fat or oil build-up
pH electrode membrane has dried out
Protein build-up in the diaphragm of a pH
electrode
Silver sulfide contamination of pH electrode Remove deposits by soaking the electrode in a thiourea solution.
Run a new calibration after treatment.
Note
Cleaning and filling solutions should be handled with the same care as that given to toxic or corrosive
•
substances.
The condition of the pH electrode can also be checked, using the provided METTLER TOLEDO method Sensor
•
Test.
SevenExcellence™
Slope: 90-94%
or offset: ± (20-35) mV
Electrode needs cleaning
Action
Either rinse the membrane with soap solution or aceton/ethanol or
shortly soak the tip of the electrode in hot water. When rinsed with
organic solvent, place the membrane overnight in 0.1 mol/L HCl.
Soak the tip of the electrode overnight in 0.1 mol/L HCl.
If this procedure has no effect, soak the tip of the electrode for a
few minutes in reactivation solution for pH electrodes.
Remove deposits by soaking the electrode in an HCl/pepsin
solution.
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Slope: 85-89%
or offset: ± (>35) mV
Electrode is defective or too old
Maintenance and Care​ ​ 23