Metrohm Spectrosense - Manual (Page 33)

3 Evaluation of photometric titrations
Spectrosense, Instructions for Use
29
3 Evaluation of photometric
titrations
The forms of photometric titration curves may vary widely. These forms
and subsequently the evaluation of the titrations depend on various
factors:
• the type of the indication: self-indicating titrations or titrations with
added indicator
• absorption or transmission curves
The indicator changes its color after the
endpoint (EP) of the titration has been
reached.
IP: Changing point of the indicator.
Evaluation: Intercept of tangents.
The indicator changes its color in the
region of the endpoint of the titration.
IP: Changing point of the indicator.
This applies for most self-indicating titra-
tions.
Evaluation: Potentiometric inflection point
evaluation.
The indicator changes its color before the
endpoint (EP) of the titration has been
reached.
IP: Changing point of the indicator.
Evaluation: Intercept of tangents.
U/mV
V/ml
IP
EP
U/mV
V/ml
IP=EP
U/mV
V/ml
IP
EP