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Gas Chromatography-Mass Spectrometry ChemDraw
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Infrared
Spectroscopy (FT-IR) The web tutorial Infrared Spectroscopy and Organic Functional Groups has more information. Apparatus Procedure CHEM 211 students may run IR spectra only during their regularly scheduled laboratory time. 1. If the OPUS software is NOT already running, select ftir_user to get to the desktop. On the desktop, double click on the OPUS 7.0 icon to start the acquisition program. When prompted, log in as student. There is no password, so click on Login to open the program. The ATR-diamond surface should be clean and free of any sample at this point. In the About OPUS window, click on OK. [The program will open and run a performance test on the instrument. You can observe the test in the lower bar of the open window. Do not touch the instrument during this performance check. When the test is completed, you should see a green circle in the bottom right corner of the window. If it is a yellow or red circle, please see an instructor or lab assistant. 2. To obtain an FT-IR spectrum, click on the green test tube icon in the icon menu bar. 3. Enter a sample name. The best sample names include the name of the compound and your initials. 4. To store your data in the correct folder, select the appropriate folder for your data in the path: field by clicking on the on the browse button . Select the correct folder in the C:\Data folder. For Chem. 105, for example, it would be C:\Data\Fall 2012\Chem105\. 5. With a clean and dry ATR-diamond surface, select Start Background Measurement.
For solid samples: place enough solid to easily cover the entire ATR-diamond and lower the plunger with the handle until it snaps into place. NOTE: it is impossible to put too much force on your solid using the plunger since it is calibrated to never apply too much force to the ATR-diamond. Select Start Sample Measurement. After four scans are run on your sample, your FT-IR spectrum should appear in the OPUS window. 7. To label your peaks, click on Evaluate in the upper menu bar and select Peak Picking. Click and drag the box in the middle of the spectrum upwards until you see peak labels on all of the peaks of interest to you. (Typically, we are only concerned with major peaks between 4000-1400cm-1.) Click on Store in the left-hand window to retain the peak labels. 8. To save your spectrum to your USB flash drive. A. Right-click on your spectrum and select, copy all. B. Open the Paint program (if it isn’t already open) and Paste in your spectrum. C. Save your spectrum as a jpeg file on your USB drive. 9. CLEAN UP! Remove your liquid sample with KimWipes or use the vacuum to remove your solid sample from the sample area. Then, use damp ethanol KimWipes to thoroughly clean the sample area and under-side of the plunger. 10. To leave the program ready for the next user, please go to the menu bar, select window in the upper menu bar and New Spectrum Window. The following is an example data table which you should use to display the data given in your infrared spectra.
(Literature IR
frequency absorptions were taken from Table 1 below) Table 1: Principal IR Absorptions for Certain Functional Groups above 1400 cm-1
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