We try to setup a used Bruker Avance 200 system. After frequency search we started to setup lock and shim file. Using D2O everithing worked quite well - the spectrometer find the lock and shimming leads to a 1H linewitdth less than 3Hz (10mm tube). Next step we wanted to set the files for acetone-d6. The system finds the lock, but now we see two well shaped lines separated by 0.48 ppm. Shimming does not solve this problem. We also tried acetone-d6 from a different bottle but still see two signals.
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[Stan NMR blog] Why are spectral lines Lorentzian
Why are spectral lines Lorentzian
Explanation of the central role of the Lorentzian lineshape in spectroscopy
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[U. of Ottawa NMR Facility Blog] CPMG to Enhance Sharp Lines
CPMG to Enhance Sharp Lines
The Carr - Purcell - Meiboom - Gill (CPMG) sequence is used to measure T2 relaxation times and more recently has made an impact in measuring the line shapes of very broad solid lines by breaking them up into spikelet patterns which mimic the static line shape. The very simple pulse sequence is shown here:http://3.bp.blogspot.com/_5wBTR2kKTqA/S2xdSaQ7iPI/AAAAAAAAAt0/kg9wRg8ccoY/s400/cpmg2.jpgDuring the (D2 - ? -D2)n period the intensity of lines with short T2 (broad lines) diminishes much more quickly than that for lines with long T2 (sharp lines). The CPMG...
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08-21-2010 08:15 PM
[Stan NMR blog] Why are spectral lines Lorentzian
Why are spectral lines Lorentzian
Explanation of the central role of the Lorentzian lineshape in spectroscopy
More...
nmrlearner
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08-21-2010 05:42 PM
NMR question about chemical shifts and frequency difference between two lines?
The 13C chemical shifts for the carbonyl and methyl resonances of acetone are 206.68 and29.92 ppm, respectively (referenced to TMS at 0 ppm).a) If this spectrum was run on a Varian INOVA 400 NMR spectrometer, what is the frequencydifference in Hz between the two lines? (Assume <ref = 100.0650368 MHz) (2 points)b) What is the difference in magnetic field experienced by the carbonyl carbon vs. the methylcarbons. (4 points)thank you Allision!!so then i haver a difference of 17,717 Hz.for b) now I do not have any textbooks for this course but i did go to the library and picked up 4 differnet...