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Standard 13C sensitivity test sample: 10% Ethylbenzene in chloroform-d.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 conventional 13C spectrum.
The calibration of the 13C sensitivity test is performed using the standard 13C parameter set (the pulse program is set to pulprog zgdc). This test is also a very critical test of the decoupler efficiency.MODIFY SPECIFIC PARAMETERSThe sensitivity is measured on the highest line in the aromatic part of the spectrum according to the equation:
S/N=2.5*(height of aromatic)/(peak to peak amplitude of noise)
Update the corresponding pulses and power levels in the acquisition parameters according to the selected solvent/probehead parameters by executing the getprosol command (pulses and power levels must be correctly set by the edprosol command). If required, any acquisition parameter can be modified manually or in the AcquPars section. It is very important to use a long recycle delay, usually d1=5*T1(13C) (for instance d1=300 s).ACQUISITIONSet p1 to the 90º 13C observe pulse at high power level pl1. If required, the CPD 1H pulses from the decoupler should be recalibrated.
Start acquisition by rga and zg (the expected experimental time is displayed with the expt command).PROCESSING
The recorded data is Fourier transformed with ft (or ef) and phase and baseline corrections are performed using apk and abs, respectively. Modify processing parameters if required from the ProcPars section or using the ased command.PLOTSee spectrum
Use the TOPSPIN plot editor (xwinplot). Plot the spectrum from 200 to 0 ppm using a CY of 12 cm for a standard A4 chart paper. Use sufficient vertical amplitude (min. 1.5 cm) to plot the noise between 120 and 80 ppm.OBSERVATIONS
Written by Teodor Parella Copyright © 1998-2008 BRUKER Biospin. All rights reserved. |