Metrohm tiamo 2.3 Patch 1 (process analysis) - Manual (Page 946)

5.6 Commands ￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭
930 ￭￭￭￭￭￭￭￭ tiamo 2.3 Patch 1 (for Process Analysis)
5.6.3.10.4 Gran evaluation
Parameters: Method ▶ DET/MET ▶ Properties... ▶ Additional evaluations ▶ Gran
evaluation
The Gran evaluation can be used to determine S-shaped DET and MET
titration curves. Two different procedures can be selected for this which
are referred to as Normalized and Standard.
In the normalized procedure, the titration curves are linearized in 2 parts:
the first part is before, the second after the equivalence point. The Gran
function G is then plotted vs. the reagent consumption to get the Gran
endpoint GP.
In the standard procedure, which is only available for 5.6.3.2.2.7DET pH
- Additional evaluations and 5.6.3.3.2MET pH, only the part before the
equivalence point will be linearized, and afterwards the intersection point
with the y axis is determined as the endpoint GP.
The Gran evaluation is only suitable for curves with a single jump. All of
the jumps are evaluated together as a group when a curve has several
jumps. This may be desirable, as for example if 2 EPs are very close to one
another in a steep jump and one wishes to have only one GP evaluated,
e.g. with titrations of NaOH that contain carbonate.