Inserting NMR Sample

Adjusting sample depth with a sample gauge

First, the NMR tube has to be inserted into a spinner turbine. For best results, NMR tubes should be positioned in the spinner turbine so that the sample volume will be centered in the NMR probe. This can be done with the help of a sample gauge, which usually has a center line and rectangular markings to indicate the probe geometry.

A sample gauge also has an adjustable bottom, which can be adjusted to allow quick posistioning of a series of identical samples. Setting a sample tube too low may cause it to break, as well as contaminate and damage the probe!

It is also important to make sure that the tube sits firmly in the spinner. If your sample slides too easily inside a spinner turbine, it may indicate that its rubber o-rings need replacement.

Inserting and ejecting

To access the Insert and Eject buttons do the following:

• VNMR - click on the Acqi button or type acqi
  
• VNMRJ - click on the Setup tab

You can also type insert or i and eject or e at the command prompt in VNMR or VNMRJ.

Sample change procedure

1. Eject the current sample first. Even if there is no sample in the magnet you need to use eject to create airflow.
2. Remove the ejected sample.
   
3. Verify that you have the airflow to support your sample. Carefully insert the sample in the bore.
4. Click on Insert to lower your sample.
   

Avoid leaving the spectrometer with an open bore for long periods of time, as this increases the risk contaminating the bore with forieign particles. If you need to remove a sample and have nothing else to measure, either insert a standard NMR sample or cover the bore with a dedicated plug.

External links

http://www.varianinc.com/image/vimage/docs/products/nmr/apps/pubs/manuals/0199916100c.pdf

http://www.varianinc.com/image/vimage/docs/products/nmr/apps/pubs/manuals/0199931300b.pdf