Metrohm tiamo 1.2 Manual - Handbuch (Seite 449)

Commands 423
STAT
Command for STAT Titrations ( STAT ).
Principle
In STAT titrations reagent is added until a preset measured value has been
reached (control point); this is then kept constant. The substance released by the
reaction is immediately titrated with the reagent to maintain the control point. The
STAT titration keeps the control point constant until the preset termination criterion
has been achieved.
STAT titrations are used, for example, in enzyme analysis where the enzyme activ-
ity can be determined from the resulting dosing rate (in mL/min).
Reagent addition takes place in three phases during the titration:
• Initial addition
During this phase the dosing rate increases continuously. It starts with the
Min. rate and increases to the Max. rate .
• Continuous addition
In this phase addition is carried out at the Max. rate until the Control range is
reached.
• Control range
In this range addition is finely controlled. Shortly before the end point is
reached addition is only carried out at the
Min. rate (see "Control range").
Commands
Depending on the measured value one of the following two STAT commands can
be chosen:
• STAT pH
STAT Titration with pH electrodes (measuring quantity pH).
• STAT U
STAT Titration with metal electrodes (measuring quantity U).