User manual MICROCAL VP-DSC

[. . . ] MicroCal, LLC 22 Industrial Drive East Northampton, MA 01060 USA Phone: +413 586 7720 Fax: +413 586 0149 Binding Stability Kinetics support@microcalorimetry. com VP-DSC MicroCalorimeter User's Manual MAU120030 Rev B Introduction Key to Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v Instrument Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii Safety Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix How to Get Help From MicroCal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x Section 1: VP-DSC System Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. 1 VP-DSC Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1. 2 Data Acquisition/Control Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. 3 Suitable Laboratory Environment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] Located in the /data sub-directory of your computer's hard drive are some sample water/water scans obtained using your instrument, at MicroCal. The water/water upscans are named waterup1. dsc waterup4. dsc, and the water/water downscans are named waterdn1. dsc ­ waterdn4. dsc. These scans are considered to be typical results, assuming a conscientious effort at duplicating the techniques described in section four. The scan parameters for waterup#. dsc and waterdn#. dsc data files can be retrieved by loading any of those same data files into the DSC Control window. The Tutorial It is assumed for this tutorial that the reference and sample cells are clean. Prepare 30-50 ml of distilled water by filtering the water, then degas with vigorous stirring for 15 minutes. When the water is ready, and when the DSC cells are cool, empty the cells then fill them using the prepared water. While filling, follow the suggested techniques mentioned in section 4. 2. Keep the water covered when not being used. The first step in carrying out the water/water scans is to set the run parameters appropriately. Since you are attempting to duplicate previous results (water/water scans carried out at MicroCal), it is crucial that we use the same run parameters that were used for our comparative scans. To accomplish this you first open the DSC Control window from the main menus, as shown below: -55- Section 5. 1 - Scanning Water/Water Initially, the last set of run parameters that were executed will be displayed, by default. To load the same run parameters as used in the waterup#. dsc scans, you will load the run parameters from the data file itself, as the run parameters used will be contained in and extracted from the data file header. From the main window, select the Load Run File button: Once the button has been selected, a dialog box will open allowing you to specify the run parameter file you wish to load. Run parameter files have a default extension of *. scn and reside in the /setup sub directory; however, for this particular example we will be loading the run parameters from a data file having a *. dsc extension and located in the /data sub directory. To load our run parameters, double click MAU120030 Rev B -56- Section 5. 1 - Scanning Water/Water your way to the /data sub directory and replace the displayed *. scn file specification with the desired *. dsc file specification. This can be done using the drop down list provided at the bottom of the dialog box ("List Files of Type. . . ") as shown below: Once you're displaying *. dsc files located in the /data subdirectory you should see the appropriate data file containing the desired run parameters. The reference water/water scans are waterup1. dsc through waterup4. dsc. and waterdn1 through waterdn4. dsc. Selecting any of these data files will load the appropriate run parameters. Select waterup1. dsc and click on OK, as shown below: The run parameters displayed within the DSC controls window are now identical to those used to generate the water/water data files on your P. C. Those specific parameters are shown below: -57- Section 5. 1 - Scanning Water/Water As can be seen, the run parameters loaded specify that 20 scans are to be carried out, scanning the VPDSC alternately up and down from 10° to 110°, at a scan rate of 90°/Hr. The prescan thermostat is set to 15 minutes for all of the scans and the filtering period is 16 seconds for all scans. At this point we neither need nor want to change any of the run parameters. [. . . ] This file is of ASCII format and can easily be edited using NotePad or WordPad. When making changes to the file be sure and save the modified file under the same name of vpviewer. ini. The file must always be saved as an ASCII file, with no rich text or control characters that are common to many word processing applications. The parameter definitions can be found immediately below: PrePulseInitialDelay: A delay, in seconds, prior to the first pressure perturbation. [. . . ]