Milwaukee MW151 MAX - Page 19

GENERAL OPERATIONS 19
For refillable electrodes:
y Refill the electrode with fresh electrolyte solution (see the electrode’s specifications
to select the correct refilling solution).
y Keep the electrode upright for 1 hour.
y Follow the storage procedure above.
If electrodes are not maintained correctly both accuracy and precision are aected. This
can be observed as a steady decrease in the slope of the electrode.
The slope (%) indicates the sensitivity of the glass membrane, the oset value (mV)
indicates the age of electrode and provides an estimation when the probe needs to be
changed. The slope percentage is referenced to the ideal slope value at 25 °C.
Milwaukee Instruments recommends that the oset does not exceed ±30 mV and that the
slope percentage is between 85-105%.
When the slope value drops below 50 mV per decade (85% slope eiciency) or the oset
at the zero point exceeds ±30mV, reconditioning may improve performance, but a change
of electrode may be necessary to ensure accurate pH measurements.
Electrode Status (MW151)
MW151 displays electrode status after calibration. See probe icon on the LCD screen.
The assessment remains active for 12 hours and is based on the electrode oset and
slope during calibration.
5 bars Excellent condition
4 bars Very good condition
3 bars Good condition
2 bars Fair condition
1 bar Poor condition
1 bar blinking Very poor condition
no bar Not calibrated
Recommendations:
y 1 bar: Clean the electrode and recalibrate. If there is still only 1bar or 1bar blinking
after recalibration, replace the probe.
y No bar: Instrument was not calibrated on current day or a one-point calibration was
performed with previous calibration not yet deleted.