Question

Hi, I am a new member to this community. I would like to set up an experiment, in which I have to set up proton carrier frequency at 7ppm during t1-evolution period and at water frequency during t3-direct detection period. How to do this? any suggestions?

Answer 1

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Hi kmd,

You'll need to set frequency offset before the "t1" excitation pulse to whatever corresponds to 7 ppm - that will cause "t1" evolution to be encoded relative to the frequency of that pulse.

Similarly - to read relative to water resonance - set transmitter offset to the water offset value just before the readout pulse.

If you have a Varian system you would do something like:

pulsesequence(){
    double myoffset;
    ...
    myoffset = getval("myoffset");
    ...
    obsoffset(myoffset);
    rgpulse(...);/* or simpulse, sim2pulse or sim3pulse */
    ...
}

Hope that someone will explain how to do this for a Bruker system or any other details.

link

answered Aug 16 '10 at 10:53

Evgeny Fadeev
577●1

updated Aug 16 '10 at 14:21

Thanks for the reply. I am working on a Bruker instrument. How to change the pulse sequence in that case. Thanks in advance - kmd (Aug 16 '10 at 11:56)

Answer 2

1

You can define a frequency list file in directory ../topspin/exp/stan/nmr/list/f1 (or f2, f3)

there you make a file containing:

O BaseFrequency of H
offset 1
offset 2
...
...

e.g.

0 600.15
2700
4200

Once you have the file, you should put 'fq1' command in a pulseprogram (fq1:f1) and define the list file in acquisition menu under 'lists'. Check noediff, std-related pulseprograms in Bruker PP library.

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answered Aug 17 '10 at 12:52

MKarjuna
11

updated Aug 17 '10 at 12:59

Evgeny Fadeev
577●1

hmm.. strange in lines breaks on example. - MKarjuna (Aug 17 '10 at 12:53)

hey, thanks for stepping in, the "literal" formatting is indented by four spaces or can be inlined with backticks - Evgeny Fadeev (Aug 17 '10 at 12:56)

the markup language used here is called markdown http://en.wikipedia.org/wiki/Markdown - Evgeny Fadeev (Aug 17 '10 at 12:57)

thank you very much - kmd (Aug 19 '10 at 09:08)

now I recall that you can specify offset for the shaped pulses separately using SPOFFS1 for sp1, etc. - Evgeny Fadeev (Aug 19 '10 at 10:27)

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