MicroCal VP-ITC User Manual page 34

VP-ITC MicroCalorimeter User's Manual
Injection Parameters
The Injection Parameters group allows you to define the volume, duration, spacing between
injections, and the filter period for each injection. At the bottom of this group is a summary table
that lists, by row number, these parameters. You may select an injection to edit by clicking on a
row to highlight it; the parameters for this injection will be entered into the text boxes. Then,
depending on the Edit Mode selected, you may edit the text boxes to effect all injections (All
Same), only the currently highlighted injection (Unique) or the currently highlighted injection
and all the following injections (Apply To Rest).
µ
Volume ( l)
Enter the volume of titrant (in micro liters), to be injected from the pipette into the sample cell for
the selected injection(s).
Duration (sec.)
Enter the time, in seconds, for the titrant to be injected into the sample cell for the selected
injection(s).
Note: VPViewer will default this value to be twice the number entered in the Volume text box.
Spacing (sec.)
Enter the time, in seconds, between the beginning of the selected injection(s) and the beginning of
the next injection.
The user is responsible for specifying enough time between the injections to allow the DT signal
to return to the baseline after an injection peak deflection. Typical values for this parameter
range from 180-300 seconds, depending on the size of the peak and the kinetics of the reaction.
Filter Period (sec.)
This is the time period (in seconds) in which the data channel conversions are averaged to
produce a single data point for plotting and saving.
For fast reactions, a filter period of 2 seconds is sufficient to obtain enough data points for
representation of the peak for accurate integration of the area. For monitoring of very long, slow
thermal processes, the filter period may be increased accordingly to avoid accumulation of excess
data points. Please note: Although there may be a practical limit for a data set size, only
available disk space would limit the number of data points that VPViewer is able to collect and
save.
Edit Mode
All Same – Selecting this option causes all injections to be assigned the same parameter values
as entered into the Injection Parameter text boxes.
Unique – This option allows you to set up injections using different parameters. You may
customize each injection to have different volumes, duration, spacing or filter periods. Editing
the Injection Parameter text boxes when this option is selected effects only the injection that is
currently highlighted in the summary table. Likewise the values displayed in the individual
parameter boxes apply only to the injection that is currently highlighted in the summary table.
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