The BSMS AutoLock function (used by the XwinNMR "lock" command,
IconNMR or from the BSMS keyboard) on our Avance300 always
locks onto the aromatic rather than the methyl peak of toluene-d8. Since
the
edlock table has the lock shift set at 2.09 ppm (methyl) the resultant
spectrum is
displaced by ca 5 ppm. The obvious solution is to change the edlock table
to have the shift of the toluene ring deuterons, but I would rather lock
onto
the methyl as it is sharper and gives a somewhat better shim. What do
other
people do when using toluene? Do you have a way of convincing the AutoLock
function to pick the methyl group? or do you simply manually lock onto the
methyl?
or do you lock onto the aromatic peaks.
On higher field machines the aromatic peaks would be spread out (and thus
less intense) so that AutoLock would pick out the methyl as the strongest
peak.
Cheers
-Kirk
Kirk Marat, Ph.D., NMR Facility Manager
Dept. of Chemistry and Prairie Regional NMR Centre
University of Manitoba
Winnipeg, Manitoba, R3T 2N2, CANADA
kirk_marat@umanitoba.ca
ph. (204) 474-6259, FAX (204) 474-7608
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