Metrohm 840 PC Control 5.0 / Touch Control - Manual (Page 206)

4.1 Titrations
194
PC Control / Touch Control
Note!
As the reagent addition in DET depends on the measuring data, the
titration curve should not vary too much from an S-shaped curve.
• Monotonic equivalence point titrations (MET) with reagent addi-
tion at constant volume increments for titrations with relatively high
signal variations or suddenly occurring potential jump and for slow
titrations or slowly responding electrodes. Measured value accep-
tance is drift-controlled (equilibrium titration) or after a waiting pe-
riod. Equivalence points are evaluated automatically.
U/mV
V/mL
Fig. 4.2: Reagent addition for MET
• Endpoint titrations (SET) for rapid routine determinations by titra-
tion to a preset endpoint (e. g. titrations according to special stan-
dards) and titrations in which an excess of reagent must be
avoided. The termination of the titration at the endpoint is either
drift-controlled or after a waiting period. The volume that has been
added when the endpoint is reached gives the calculable reagent
consumption.
t/s
EP
Control
range
Continuous
addition
Initial
addition
V/mL
V/mL
U/mV
Fig. 4.3: Reagent addition for SET