Xylem pH/ION 3400i ION SELECTIVE ELECTRODE ANALYZER User Manual
Page 36
Operation
pH/ 3400i
36
Preparatory activities
Perform the following preparatory activities:
Note
For calibration, use tempered standard solutions with a temperature
that differs by maximum
±
2 °C from the temperature of the test sam-
ple.
Standard solutions
Use two or three different standard solutions from the following selec-
tion. In the three-point calibration, the standards must be selected in
either ascending or descending order.
With a two-point calibration, the calculated slope is used for the entire
measuring range of the electrode. With a three-point calibration, the en-
tire measuring range is divided into measuring range I and II. Different
calibration values apply for the two measuring ranges. The measured
value of standard solution 2 separates the two measuring ranges from
each other.
Note
Among other things, the measuring accuracy depends on the selected
standards solutions. Therefore, the standard solutions selected should
cover the expected value range of the following concentration mea-
surement.
1
Connect the ion selective electrode and the reference elec-
trode to the measuring instrument.
2
Connect a temperature sensor (sockets 2 and 4, see
section 1.5 J
3
If necessary, press the
play ISE appears.
4
Keep tempered standard solutions ready.
Parameter
Values [mg/l]
Std 1
0.01 / 0.02 / 0.05 / 0.1 / 0.2 / 0.5 / 1 / 2 / 5 / 10 / 20 /
50 / 100 / 200 / 500 / 1000
If Std 2
>
Std 1, Std 3 must be
>
Std 2
If Std 2
<
Std 1, Std 3 must be
<
Std 2
Std 2
Std 3