MicroCal VP-ITC User Manual page 33

Data File Name
Following Windows filename requirements enter up to 16 characters for the filename. The
program will automatically add .ITC for an extension name, so that the raw data file will be
recognized by Origin as a VP-ITC data file. Do not start the filename with a number nor include
any hyphens, periods or spaces in the filename, as Origin will not accept the file. Please note:
Origin for ITC data analysis can only distinguish a difference in file names for the first 10
characters, therefore if you will be analyzing more than one data file in a single session of Origin
make sure that each file name has a unique combination of characters within the first 10.
Feedback Mode/Gain
Select one of the three available modes, None, Low or High (High is recommended for most ITC
experiments).
The feedback modes can be described as active (Low or High) or passive (None). High gain will
provide the fastest response time, while passive mode (None) will provide the highest sensitivity
(slowest response time). Most ITC reactions will require using the High gain feedback mode,
which yields the fastest response time. Monitoring of long, slow thermal process in the VP-ITC
(i.e. kinetics, metabolic rates) might benefit from using the passive or low gain feedback modes.
ITC Equilibration Options
This group of check boxes determines how VP-ITC will equilibrate before collecting data for the
experiment. To start an experiment in the shortest possible time put a check mark in each box.
No Check Temp. – When this check box is selected the Cell Temperature (°C) text box entry
will be ignored and the experiment will start at the current cell temperature. Otherwise the cell
will equilibrate at the temperature entered into the Cell Temperature (°C) text box before the
experiment can start. Please Note: When there is not a check mark next to the No Check Temp.
option, the cell sample should be cooled (before loading) far enough below the experimental
temperature, so that after loading, the temperature of the sample will be at or below the
experimental temperature. If the loaded cell sample is at a higher temperature, there will be a
long equilibration period before the experiment will begin. (See page 78 for more information).
Fast Equil. – When this check box is selected, VPViewer will not establish a non-stirring
equilibration period. This will allow for slightly faster equilibrations and in general is the best
way to run the ITC. There may be instances where the operator would like to view a non-stirring
baseline and can do so by removing the check mark next to this option.
Auto – When this check box is selected the ITC experiment will proceed through the
equilibration states (Pre-stirring and Final Baseline) and complete the experiment without any
further interaction from the user. Users can still force the an equilibration states to the next
equilibration state by double clicking on the DP data box, just as is done with the auto-start option
inactive.
Data File Comments
You may type into this text box comments about your experiment to be saved in the header of the
data file for future reference.
Section 2: VPViewer and Origin Software
23