How to use NMR machine? (NMR Basic Operation)

Summary

This video provides a comprehensive guide to using a 500 MHz NMR machine, covering essential safety precautions, equipment handling, and software commands. The training walks users through the setup process, sample insertion, and critical commands in TopSpin 3.2 for creating files, tuning the probe, shimming the magnet, and acquiring and processing spectra. Key tips for handling samples and troubleshooting are highlighted, such as ensuring proper sample depth and cleaning, as well as techniques for accurate phase and baseline correction. The tutorial aims to equip users with the knowledge to independently conduct NMR experiments and process data efficiently.

Takeaways

• 😀 The NMR machine has a strong magnetic field, which can be harmful to people with pacemakers or pregnant women. Always exercise caution and ask for help if needed.
• 😀 Electronic devices like watches, phones, and credit cards should be kept at least one meter away from the NMR machine to avoid damage.
• 😀 When preparing your sample, always use the appropriate spinner and ensure the sample depth is correct to avoid issues with shimming and locking.
• 😀 Before loading your sample, clean the bottom of the NMR tube to ensure high-quality data and prevent contamination.
• 😀 The NMR machine is equipped with an auto-sampler that makes sample loading easier without needing to climb the ladder.
• 😀 In the software, use the command `edc` to create a new file, and make sure to choose the correct experiment package and solvent.
• 😀 Use the command `atma` to tune the probe frequency before starting experiments, as tuning is necessary for accurate signal detection.
• 😀 The `rsh shims.best` command should be used to load the most recent good shimming parameters to improve the quality of your data.
• 😀 The locking process, done with the command `lock`, compensates for slight magnetic field drifts and ensures a stable and clear spectrum.
• 😀 After completing the experiment, use the command `ej` to safely eject the sample from the machine.

Q & A

What should you do before approaching the NMR machine if you have a pacemaker or are pregnant?

If you have a pacemaker or are pregnant, you should seek assistance from your workmates before getting closer to the NMR machine, as the strong magnetic field could be harmful in such cases.

Why is it important to keep watches, credit cards, or cell phones away from the NMR machine?

The NMR machine has a very strong magnetic field that can damage or destroy items like watches, credit cards, and cell phones, including erasing their memory or interfering with their functionality.

What is the purpose of the crowd probe in the NMR machine?

The crowd probe enhances the sensitivity of the NMR signal. It is important to ensure that the probe is ready before running experiments. If the probe shows a blinking blue light or any other issue, it should be reported immediately.

What is the importance of using a sample gauge when loading the NMR tube?

The sample gauge ensures the correct depth of the sample in the NMR tube. If the tube is inserted too deep, it can get stuck, and if it is too shallow, it can lead to issues like poor locking or shimming during the NMR experiment.

What should you do before loading a sample into the NMR machine?

Before loading the sample, always wipe the bottom part of the NMR tube to remove any dirt that could affect the resolution of the NMR spectrum. Additionally, ensure that the sample tube is free of cracks or stains.

What does the 'edc' command do in the TopSpin software?

'edc' is used to create a new file for an NMR experiment. You will be prompted to give the file a name and select the necessary experiment parameters.

What is the 'atma' command used for in NMR experiments?

'atma' is used to tune the probe frequency to match the nuclei of the sample. This step is critical before running experiments like Carbon-13 NMR after Proton NMR to ensure proper signal detection.

Why is shimming necessary in NMR, and how do you perform it?

Shimming is necessary to eliminate inhomogeneities in the magnetic field, which can distort the NMR signals. The 'rsh shims.best' command loads a generally good shim set, but you may need to fine-tune the shimming for each specific sample.

What is the purpose of the 'lock' command in NMR?

The 'lock' command compensates for any drift in the magnetic field during the NMR experiment. This is crucial to maintain signal quality and sharpness, and it helps calibrate the chemical shift using the deuterium signal from the solvent.

How do you handle the baseline correction in an NMR spectrum?

To correct the baseline, you should first check the automatic phasing using the 'apk' command. If necessary, manually adjust the phase using the 'adjust phase' tool. Afterward, apply the 'abs' command for baseline correction, which usually works for routine experiments.

What does the 'integrate' command do in the NMR software?

'integrate' automatically measures the area under peaks in the NMR spectrum, which reflects the relative concentration of different components. You can also manually adjust the integration if needed, especially if the automatic process is not accurate.

What should you do after completing your NMR experiment?

After finishing the NMR experiment, use the 'ej' command to eject your sample. Ensure the data is saved properly before exiting the software, as 'stop' will discard any unsaved data.