Metrohm 726 Titroprocessor - Manual (Page 66)

4.3 Sensors
726 Titroprocessor, Instructions for use 60 60
Buffer solutions
As buffer solutions can have very different compositions it is necessary to
give the correct buffer type so that the temperature correction is correctly
used for the calibration.
Select a buffer type or manufacturer. Insert a buffer series into the buffer
table by pressing the [Preset series] softkey or [Add series].
Calibration is also possible without a predefined buffer list. The buffer (type
and value) can be entered individually. Different types of buffer can also be
used. If your type of buffer is not contained in the selection list then select
'none'.
Enter the nominal value of your buffer solution in the line
Buffer 1 pH
and start a measurement with the [Start Stop] softkey.
During the calibration the values found are compared with the predefined
values of the buffer solutions (theoretical value, temperature with automatic
temperature measurement) and subjected to a plausibility test, see page
117. If this should cause annoying error messages with 'exotic’ buffers or
'unusual’ sensors then select buffer type 'custom' for user-defined buffer
types. No plausibility tests are carried out in this setting.
After each buffer solution measurement the calibration values are entered in
the buffer table.
# Buffer pH val. T[§C] pH cor. Val.[mV]
ДДДДДДДДДД ДДДДДДД ДДДДД ДДДДДДД ДДДДДДДД
1 Metrohm 4.000 23.0 3.996 175.6
2 Metrohm 7.000 23.0 7.008 0.9
The buffer table includes the following data:
• buffer type or manufacturer
• nominal pH
• buffer temperature
• (temperature)-corrected effective pH
• measured potential in mV
When a measurement has been completed the next buffer solution can be
entered and measured.
After at least two measurements have been made the calibration curve can
be displayed by pressing the [Show curve] softkey. The corresponding
values for the slope and the asymmetry pH (pH
as
) are shown together with
the calibration curve.