Metrohm tiamo 2.2 (ProcessLab) - Manual (Page 801)

￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭ 5 Method
tiamo 2.2 (ProcessLab) ￭￭￭￭￭￭￭￭ 785
Dynamics
The control range is entered as distance to the endpoint. Within the control
range, iodine will be generated in steps which are controlled by the mini-
mum rate. The larger the control range, the slower the titration. Outside
the control range, iodine will be generated continuously with Maximum
rate.
The standard control parameters are optimal for most applications and
should not be modified. If you nevertheless need to modify the control
parameters for special reagents and/or samples take care that the polariza-
tion current of the indicator electrode (I(pol)), the endpoint and the control
range are linked to each other.
756, 831
Range
1.0 ... 2000 mV
Default value 120.0 (slow), 70.0 (optimal), 30.0 (fast) mV
851, 852
Range
0.1 ... 1250.0 mV
Default value 120.0 (slow), 70.0 (optimal), 30.0 (fast) mV
The diagram shows KF titration curves at different polarization currents. It is
clear to see that the position of the endpoint varies with the polarization
current. The curves have different slopes, i.e. dynamics must also be adap-
ted. Polarization currents smaller than 10 µA are not suitable for this
application. The following table gives an idea of the optimal control param-
eters for various polarization currents.