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== Adjusting sample depth with a sample gauge  ==
== Adjusting sample depth with a sample gauge  ==


The optimal volume for NMR samples is 500-600 uL for 5 mm regular NMR tubes and ~300 uL for 5 mm Shigemi tubes. Before the tube is put into the magnet, the optimal position of the tube in the sample holder should be measured in the gauge as shown in the figure below.<br>  
[[Image:Gauge sch.jpg|right|100px]]First, the NMR tube is needed to be inserted into a spinner turbine. For best results, NMR tubes should be positioned in the spinner turbine in such a way that the sample remains centered in the r.f. coil region inside 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.<br>  


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 should be done with the help of a sample gauge, which usually has a center line and rectangular markings to indicate the probe geometry.<br>
A sample gauge also has an adjustable bottom, which can be adjusted to allow quick positioning 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!


<br>
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 the rubber o-rings of the spinner need replacement.


A sample gauge also has an adjustable bottom, which is typically fixed at a proper level by your NMR facility manager. Never position a tube lower than the bottom of the gauge! Setting a sample tube too low may cause it to break, as well as contaminate and damage the probe!
== Inserting and ejecting  ==


<br>  
To access the '''Insert''' and '''Eject''' buttons do the following:<br>  


It is also important&nbsp; to make sure that the tube sits firmly in the spinner. If your sample slides too easily inside a spinned, that may indicate that its rubber o-rings need replacement.
*VNMR - click on the '''Acqi''' button or type <tt>acqi</tt><br>  
 
*VNMRJ - click on the '''Setup''' tab
<br>  


'''Figure1. Positions of NMR tube in the gauge'''. Left, regular tube; right, shigemi tube. <br>
You can also type <tt>insert</tt> or <tt>i</tt> and <tt>eject</tt> or <tt>e</tt> at the command prompt in VNMR or VNMRJ.  


    [[Image:Gauge reg.jpg]][[Image:Gauge sch.jpg]]
Sample change procedure


== Inserting and ejecting  ==
#Eject the current sample first. Even if there is no sample in the magnet you need to use eject to create the upward thrust using the airflow.
#Remove the ejected sample.<br>
#Place the sample in the spinner in the bore. Verify that you have the airflow to support your sample while still holding the sample. Leave the sample.
#Click on Insert to lower your sample.<br>


In VNMR:
Avoid leaving the spectrometer with an open bore for long periods of time, as this increases the risk of contamination of the bore with foreign 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.


#Click on the '''Acqi''' button or type <tt>acqi</tt>
<br>  
#Use the '''Insert''' and '''Eject''' buttons in the '''Acqi''' window


In VNMRJ:
== External links  ==


#Click on the '''Setup''' tab
http://www.varianinc.com/image/vimage/docs/products/nmr/apps/pubs/manuals/0199916100c.pdf
#Uset the '''Insert sample''' and '''Eject sample''' buttons in the middle of the screen


You can also type <tt>insert</tt> or <tt>i and eject</tt> or e at the VNMR or VNMRJ prompt.  
http://www.varianinc.com/image/vimage/docs/products/nmr/apps/pubs/manuals/0199931300b.pdf


Procedure
<br>


#Eject the current sample first. Even if there is no sample in the magnet you need to use eject to create the airflow.
== Working with Bruker Instruments  ==
#Remove the ejected sample.
#Verify that you have the airflow to support your sample. Carefully insert the sample in the bore.
#Select insert to lower your sample


<br> '''Figure2. Acquisition window.''' <br>
As with Varians, the sample tube is loaded into a spinner and the depth is adjusted using a depth gauge.&nbsp; The base of the depth gauge should be set to the minimum sample tube depth allowed by the probe in use.&nbsp; DO&nbsp;NOT&nbsp;adjust this level.&nbsp; The minimum volume depth for most Bruker probes is normally smaller than that for Varians, as a result it is important to use Shigemi tubes suitable for use with Bruker probes (they will have a shorter glass base).  


    [[Image:Acq window.jpg]]
<br>


<br> Do not leave the spectrometer with an open bore for long periods of time. If you have to remove a sample and have nothing else to measure, either insert a standard NMR sample or cover the bore with a dedicated plug.  
Samples are manually ejected and inserted into the magnet using the sample eject/insert button on the BSMS panel; the button is located in the top left corner of the BSMS.&nbsp; Samples can also be ejected using the command line in Topspin (command, ej).&nbsp;


<br>
The procedure for inserting the NMR sample into the magnet is analogous to Varians:


-- Main.GaohuaLiu - 24 Jan 2007
#Eject the current sample.&nbsp; Pressing the eject button on the BSMS (green light comes on) will initiate an upward airflow and the current sample will float to the top of the bore.
#Replace the current sample with the new sample.
#Pressing the eject button again on the BSMS (green light turns off) stops the airflow and the sample is slowly lowered into the magnet.&nbsp;
#Look for the sample lock to ensure the sample is properly sitting in the probe.

Latest revision as of 16:08, 9 December 2009

Adjusting sample depth with a sample gauge

Gauge sch.jpg

First, the NMR tube is needed to be inserted into a spinner turbine. For best results, NMR tubes should be positioned in the spinner turbine in such a way that the sample remains centered in the r.f. coil region inside 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 positioning 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 the rubber o-rings of the spinner 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 the upward thrust using the airflow.
  2. Remove the ejected sample.
  3. Place the sample in the spinner in the bore. Verify that you have the airflow to support your sample while still holding the sample. Leave the sample.
  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 of contamination of the bore with foreign 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


Working with Bruker Instruments

As with Varians, the sample tube is loaded into a spinner and the depth is adjusted using a depth gauge.  The base of the depth gauge should be set to the minimum sample tube depth allowed by the probe in use.  DO NOT adjust this level.  The minimum volume depth for most Bruker probes is normally smaller than that for Varians, as a result it is important to use Shigemi tubes suitable for use with Bruker probes (they will have a shorter glass base).


Samples are manually ejected and inserted into the magnet using the sample eject/insert button on the BSMS panel; the button is located in the top left corner of the BSMS.  Samples can also be ejected using the command line in Topspin (command, ej). 

The procedure for inserting the NMR sample into the magnet is analogous to Varians:

  1. Eject the current sample.  Pressing the eject button on the BSMS (green light comes on) will initiate an upward airflow and the current sample will float to the top of the bore.
  2. Replace the current sample with the new sample.
  3. Pressing the eject button again on the BSMS (green light turns off) stops the airflow and the sample is slowly lowered into the magnet. 
  4. Look for the sample lock to ensure the sample is properly sitting in the probe.
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