wtw inoLab 740, Operating Manual

Page: 116 / 274

Ion concentration
116
7.4.2 Standard Addition ( Std Add )
In the "Standard addition" procedure, a known amount of
standard solution is added to the sample.
The ion concentration in the sample is calculated from the
change in potential.
10 Select the ISE Adv. menu item with
82
.
11 Confirm the ISE Adv. menu item with
g
.
The menu with the measuring methods opens.
12 Select a method with
82
.
13 Confirm the method with
g
.
Measurement with the selected method begins.
1 Select the measuring method (see section 7.4.1).
2 Prepare two standard calibration solutions.
3 Perform a two-point calibration according to the user
guidance.
4 As soon as a stable value for the second standard
calibration solution is reached, the
display indicator
h
stops flashing. The slope (mV) of
the electrode is displayed after the two-point
calibration. The probe symbol shows the electrode
evaluation after the two-point calibration.