Operational Guide
22
pH
Calibration
Preparation
Pour small quantities of the bu er solutions into clean beakers. If possible,
use plastic to minimize any EMC interferences. For accurate calibration and to
minimize cross-contamination, use two beakers for each bu er solution; one
for rinsing the electrode and one for calibration. If you are measuring in the
acidic range, use pH 7.01 or 6.86 as the rst bu er and pH 4.01 (or 3.00*) as the
second bu er. If you are measuring in the alkaline range, use pH 7.01 or 6.86 as
rst bu er and pH 10.01 or 9.18 as the second bu er.
* pH 3.00 is only visible when using speci c pH electrodes and will replace 4.01
pH bu er.
Procedure
Calibration can be performed using up to ve calibration bu ers. For accurate
measurements, a minimum of a three-point calibration is recommended. The
calibration bu er can be selected from the calibration bu er list that includes
the custom bu ers and the standard bu ers:
pH 1.68, 4.01 (pH 3.00), 6.86, 7.01, 9.18, 10.01 and 12.45.
The custom bu ers allow the user to calibrate in a bu er solution di erent from
a standard one. Two custom bu ers can be set in SETUP menu. See page 23 for
more information about using custom bu ers.
The instrument will automatically skip custom bu ers which are in a ±0.2 pH
window of an already calibrated bu er.
Submerse the pH electrode approximately 3 cm (1¼”) into a bu er solution and
stir gently. Press CAL to enter calibration.
The “CAL” tag will appear and the “7.01” bu er will be
displayed on the third LCD line. If necessary, press the
ARROW keys to select a di erent bu er value. The “
”
along with “STIR” tag will be displayed and “WAIT” will
blink on the LCD until the reading is stable.
When the reading is stable and close to the selected
bu er, “CFM” tag will blink. Press CFM to con rm
calibration.
After con rming the rst point, the calibrated value
will be displayed on the rst LCD line and the second
expected bu er value on the third LCD line (i.e. pH
4.01).
To Next Page
Loading...
Need help?
General
