How do I measure a spectrum?
The following procedure takes you through the data measurement process for the most commonly used techniques: attenuated total reflection (ATR), transmission, DRIFTS, and specular reflection.
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For additional information about preparing the system and starting OMNIC Paradigm software, see the OMNIC Paradigm software Help menu or the knowledge base at: https://knowledge1.thermofisher.com/ The software may display various prompts during the measurement. If any prompts appear, follow the instructions shown on the screen. |
- Start OMNIC Paradigm software.
Make sure the sampling accessory is properly installed in the sample compartment:
| If you have... | You should... |
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An ATR accessory
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Make sure the pressure device, if included, is not in contact with the crystal. Clean the crystal with a soft cloth and, if needed, an appropriate solvent. See the documentation for your ATR accessory and crystal type for details. Generally, it is recommended to use isopropanol. If your sample requires a harsher solvent to clean it, please check the chemical compatibility sheet for your ATR accessory. |
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The Smart OMNI-Transmission accessory
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Make sure no samples that would block the infrared beam are installed in the accessory. |
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A DRIFTS accessory
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Make sure the slider is pushed in to the second cup (the one closer to the handle). This positions the gold disk in the beam. |
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A specular reflection accessory
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Place the gold mirror (provided with the accessory) face down on the accessory. |
- Press the blue Touch Point button on the integrated touch panel to measure a background spectrum.
Alternatively:
Select Preview and Measure Background in OMNIC Paradigm software. This will create a spectra tab. Then, select Start Background Measurement and wait for the process to complete.
- Next, install a sample:
| If you have... | You should... |
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An ATR accessory
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Place the sample on the crystal and apply pressure. A good first sample might be a credit card or a piece of plastic. For liquids, no pressure is needed. |
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The Smart OMNI-Transmission accessory
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Slide a sample into place. A good first sample is a plastic bag or any polymer film. |
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A DRIFTS accessory
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Fill the cup with a sample. A good first sample is a ground aspirin tablet diluted to 3- 5% in KBr powder. You do not need to overfill the cup. |
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A specular reflection accessory
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Place the sample upside down on the accessory. A good first sample is a piece of shiny metal, like aluminum, with a thin coating of vegetable oil. Add a drop of oil, then wipe the metal with a cloth so that a thin layer of oil remains. |
- Now, press the blue Touch Point button on the integrated touch panel to measure a sample spectrum. Alternatively:
In OMNIC Paradigm software, select Start Sample Measurement in the spectra tab and wait for the process to complete.
When the data measurement is complete, the sample spectrum will be displayed.
You can change your measurement name to whatever you desire. If you do not, the default name will simply be the date and time of measurement.
- Finally, you can verify, identify, and quantify your data.
| If you want to... | You can... |
| Verify the purity or quality of your sample | Use the OMNIC Paradigm software QCheck tool under Identify > QCheck (you can also reach it by selecting the QCheck button in the toolbar). Then select the reference spectrum you want to compare. The result will display in the Results pane to the right. |
| If you want to... | You can... |
| Quantify the amount of a component in your sample |
Use the features in the TQ Analyst software to develop custom analytical methods as QNT files, then run them in OMNIC Paradigm software with a Quantify analysis type.
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