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The pH meters available are made by different
manufacturers. The calibration procedure varies
slightly for the different models.
a)
Fisher Scientific Accumet pH meters
These meters must be set to STANDBY whenever
the electrode will be moved from one
solution to another.
i)
Measure the temperature of the solution
and set the pH meter to the same temperature using the
temperature adjustment knob (generally
it will be room temperature, 20-22
C).
ii)
Rinse the electrode with distilled water
and dry it with a kimwipe tissue.
iii)
Using the standard buffer of pH 7.00,
turn to “pH” and set the meter display to 7.00 using the
“standardize knob”.
iv)
Rinse and dry the electrode.
v)
Using the standard buffer of pH 4.00,
turn to “pH” and set the meter display to 4.00 using the
“slope knob”.
vi)
Rinse and dry the electrode and store
it in the “storage buffer” until required.
b)
VWR Scientific pH meter, Model 8000
i)
Press “MODE”
key to move the pH meter from the “standby” position.
ii)
Press “Cal”
key to initiate calibrations sequence. CAL is displayed for
2 seconds, then SLP is
displayed for 2 seconds.
iii)
The display will show the calibration
mode, pH 7-4. Press “yes”
to accept this calibration
mode.
iv)
pH 7 will be displayed for two seconds.
Rinse and dry the electrode, then immerse the
electrode in pH 7.00
standard buffer. The pH meter is calibrated for pH 7.00 when
the
ready light comes on. Press “yes”
to accept the calibration.
v)
pH 4 will be displayed for two seconds.
Rinse and dry the electrode, then immerse the
electrode in pH
4.00 standard buffer. The pH meter is calibrated for pH
4.01 when the
ready light comes on. Press “yes”
to accept the calibration. SLP will be displayed for two
seconds, then the calculated slope is
displayed. The pH meter automatically goes into the
MEASURE mode. The
READY light comes on when the reading is stable.
The pH meter
is then ready to use.
vi)
Rinse and dry the electrode and store
it in the “storage buffer” until required.
