wtw inoLab 740, Operating Manual

Page: 127 / 274

Ion concentration
127
7.4.6 Sample Subtraction ( Smp Sub )
In the "Sample Subtraction" procedure, a known amount of
sample is added to the standard solution.
The ion concentration in the sample is calculated from the
change in potential.
The sample subtraction is one method for the indirect
determination of ions. It is used for the determination of ions
for which no direct determination is possible.
A sample addition of 1% of the volume of the standard
solution prevents the sample matrix having an interfering
influence on the measurement.
13 Terminate the measurement with [Start] .
14 Start a new measurement with [Next] .
15 Repeat steps 5 - 14 for all samples.
16 Terminate the measurement with [ESC] .
A security prompt appears
17 Select Yes with [Next] .
18 Confirm Yes with
g
.
The measurement is terminated.