Metrohm 840 PC Control 5.0 / Touch Control User Manual

Page 207

Parameters

PC Control / Touch Control

195

• Karl Fischer titration (KFT) for determining the water content by

the Karl Fischer method with automatic pre- and post-conditioning.

A typical feature of the Karl Fischer titration is the controlled reagent

addition, which depends on the control difference (current meas-

ured value – endpoint), with the aim of reaching the measured value

given as being the predefined target endpoint as quickly and accu-

rately as possible. Overtitrating is avoided to a great extent. The ti-

tration termination at the endpoint takes place either drift-controlled

or after a waiting period. The volume added up to the endpoint

gives the calculable reagent consumption.

KFT Ipol

KFT Upol

V/mL

Control

range

Continuous

addition

Initial

addition

V/mL

U/mV

t/s

I/mA

Fig. 4.4: Reagent addition for KFT

The measuring modes pH (potentiometric pH measurement), U (po-

tentiometric voltage measurement), Ipol (voltametric measurement with

selectable polarization current) and Upol (amperometric measurement

with selectable polarization voltage) can be selected for all titrations.