Xylem handylab pH 12 - Manual (Page 31)

handylab pH 12 Operation
31 ba75368e04 01/2011
4.3.3 ConCal
Single-point
calibration
Use any buffer solution for this rapid method.
The calibration will be the more exact the nearer the pH value of the buffer
solution is to that of the test sample.
Two-point
calibration
For this procedure, use two buffer solutions:
z pH 7.0 ± 0.5
z any other buffer solution
Note
Skip the steps 2 and 9 if you use a pH electrode with a temperature sensor.
Note
At this point, the ConCal calibration can be broken off with <M>. This corre-
sponds to a single-point calibration. For this, the instrument uses the
Nernst slope (-59.2 mV/pH at 25 °C) and the specified asymmetry of the elec-
trode.
1 Press the <CAL> key repeatedly until the display ASY and the
function display ConCal appears. The sensor symbol displays
the evaluation of the last calibration (or no sensor symbol in the
delivery state or after the measurement parameter has been
reset).
2 If necessary, enter the temperature of the first buffer solution
with <
▲> <▼>.
3 Immerse the pH electrode in the first buffer solution (pH 7.0 ±
0.5 in two-point calibration).
4 Press the <RUN/ENTER> key.
The measured pH value appears on the display.
5 Set the measured value to the nominal pH value of the buffer
solution (at the current temperature) with <
▲> <▼>.
6 Press the <RUN/ENTER> key. The value of the asymmetry
(mV) and the sensor symbol appear on the display.
7 Press the <RUN/ENTER> key. SLO appears on the display.