View source

From NMR Wiki

You do not have permission to do that, for the following reason:
The action you have requested is limited to users in the group user.
You can view and copy the source of this page:
{{bruker-pulse-sequence
|name=selmlgp.2
|synopsis=selective 1D TOCSY with zero quantum filter
|family=[[DPFGSE 1D TOCSY]]
|medium=Liquids
|author=
|dim=1
|nuclei=H
|observe=H
|comment=documented revision 1.11.2.3
}}
[[Category:TOCSY]]
[[Category:DPGFSE]]
[[Category:MLEV17]]
[[Category:Small molecule]]

==Introduction==
The '''selmlgp.2''' is a pulse sequence for Bruker epuipment. It is a selective 1D version of 2D TOCSY using excitation sculpting technique with  pulsed field gradients (PFG). This experiment can be used to identify impurities, analysis of mixtures, substances with glycosides units or peptides, overlaped signals and also to determine the coupling constant <sup>2,3</sup>J<sub>CH</sub>.

'''Standard parameters''' might be accessible on your system under name '''SELMLGP''' or '''SELMLZF'''. If so, then typing '''rpar SELMLGP''' will load them, and only RF-pulse parameters will need to be adjusted. (the parameters is very similar to [[1D NOESY (selnogp - Bruker)]])

This pulse sequence uses a single DPFGSE element for the selective excitation with a suppression of zero quantum coherence.

==Delays==
'''d1''' - recycling delay (1-5 x T1) (usually 2 s)

'''d9''' - mixing time (the value depends on how many step of magnetization transfer will desire. For 1D COSY type spectra, use 20-30 ms. For further steps can be used to transfer up to 120 ms.)

'''d16''' - gradient recovery delay (depends on the probe) may be on the order of 100-500 &mu;s.

==Carrier frequencies==
'''O1''' (or '''O1P''' for the value in ppm) is the carrier frequency used for the hard pulses.

Parameter '''spoffs2''' - may be used as an offset for the selective excitation.

If '''O1''' is set exactly at the selectively excited resonance, then '''spoffs2''' must be zero.

In most cases it will be more optimal to set '''O1''' at the center of spectrum and enter '''spoffs2''' as a difference in Hz between the resonance of interest and the carrier frequency applied to the hard pulses.

==Hard RF pulses==
'''p1''' - {{1H}} {{90}} pulse at power level '''pl1'''

Hard pulses are applied at O1 (or O1p) carrier frequency.

==Selective RF pulse==
There is one shaped selective pulse with the following adjustible parameters:

Note: '''pl0''' must be at '''120'''.

* '''p12''' - length (default 30 ms, but generally length should be chosen according to desired selectivity)
* '''sp2''' - power level
* '''spnam2''' - waveform file name (default '''Gaus1.1000''' - gaussian pulse with 1000 steps. Can be used a gaussian curve with 5% truncated to increase selectivity)
* '''spoffs2''' - offset in Hz relative to O1 - the carrier frequency

==Gradient pulses==

* '''p16''' (default 1 ms) - length used for the gradient pulses '''gp1''' and '''gp2'''
* '''gp1''' and '''gp2''' strengths of the two gradient pulses.
* '''gpnam1''' and '''gpnam2''' - shapes of gradient pulses (default - '''SINE.100''')

Suggested ratio of '''gp1'''/'''gp2''' - 15/40

==Processing Parameters==

* '''EM''' - Exponential multiplication to reduce the noise from spectrum (usually 0.3)

Process the FID with command EM and FP (or use EFP - a combination of EM and FP command).

==References==
<biblio>
#kessler86 bibtex=@article{kessler1986transformation,
  title={{Transformation of homonuclear two-dimensional NMR techniques into one-dimensional techniques using Gaussian pulses}},
  author={Kessler, H. and Oschkinat, H. and Griesinger, C. and Bermel, W.},
  journal={Journal of Magnetic Resonance (1969)},
  volume={70},
  number={1},
  pages={106--133},
  year={1986},
  publisher={Elsevier}
}
#1d-noe bibtex=@article{stonehouse1994ultrahigh,
  title={{Ultrahigh-quality NOE spectra}},
  author={Stonehouse, J. and Adell, P. and Keeler, J. and Shaka, AJ},
  journal={Journal of the American Chemical Society},
  volume={116},
  number={13},
  pages={6037--6038},
  year={1994},
  publisher={ACS Publications},
  url={http://dx.doi.org/10.1021/ja00092a092}
}
#dpfgse bibtex=@article{stott1995excitation,
  title={{Excitation sculpting in high-resolution nuclear magnetic resonance spectroscopy: application to selective NOE experiments}},
  author={Stott, K. and Stonehouse, J. and Keeler, J. and Hwang, T.L. and Shaka, AJ},
  journal={Journal of the American Chemical Society},
  volume={117},
  number={14},
  pages={4199--4200},
  year={1995},
  publisher={ACS Publications},
  url={http://dx.doi.org/10.1021/ja00119a048},
}
#mlev bibtex=@article{bax1985mlev,
  title={{MLEV-17-based two-dimensional homonuclear magnetization transfer spectroscopy}},
  author={Bax, AD and Davis, D.G.},
  journal={J. magn. Reson},
  volume={65},
  number={2},
  pages={355--360},
  year={1985},
  url={http://spin.niddk.nih.gov/bax/lit/spdf/62.pdf},
}
</biblio>
Templates used on this page:
Return to 1D TOCSY for Bruker (selmlgp.2).
Retrieved from "http://nmrwiki.org/wiki/index.php?title=1D_TOCSY_for_Bruker_%28selmlgp.2%29"
View source

From NMR Wiki

Views

Personal tools

navigation

community

Contents

Toolbox
