(for CPD) |
Sample: ASTM sample (60% benzene/40% p-dioxane)PARAMETER SETInsert the sample (ij). Choose the solvent deuterium signal with the lock command Tune and match the probehead (wobb or atma if required). Optimize the shim procedure (read an optimized shim file with the rsh command or performs a gradshim if required). Record a conventional 1H spectrum. Record a 1H-coupled 13C spectrum.
The calibration of the low-power 90º 1H pulse via the decoupler channel is performed using the standard 13C parameters (the pulse program is decp90).MODIFY SPECIFIC PARAMETERS
The initial values are p1=90º 13C observe pulse at high power level pl1, d2=1/(2*JCH) and ns=1. It is very important to use a long recycle delay, usually d1=5*T1(13C) (d1=60 s).ACQUISITIONOn the other hand, we select a specific resonance to be monitored as a function of the pulse length. From this resonance we define the phase correction (using the phase subroutine) and the plot region (using the DefPlot button) to be monitored. o1 and o2 are set on-resonance of the selected 13C and 1H resonances, respectively.
Start acquisition by rga and zg using an initial value of p3=0us at low power level pl2. A typical antiphase pattern is observed.PROCESSINGRepeat the experiment increasing the value of p3.
In practice, p3 can be fixed to 80 usec and the user varies the power level pl2 until a nul point is achieved (this is the low-power 90º 1H decoupler pulse).
Use standard 13C processing parameters (efp with lb=3.5). After proper phasing, the first spectrum shows an antiphase triplet with the two outer lines in phase and the center line in opposite phase. When p3 is increased, the signal intensity of this triplet signal is decreased until a nul point is achieved (this is the 90º 1H decoupler pulse).
Use the TOPSPIN plot editor (xwinplot)OTHER RELATED VERSIONS
Written by Teodor Parella Copyright © 1998-2008 BRUKER Biospin. All rights reserved. |