My question for today concerns locking using the deuterium signal from
the solvent. Our spectrometer is currently 'sick' in this respect, there
being no signal from the lock transmitter. I have always been given to
understand that one can obtain spectra unlocked and that the main
disadvantage of this is that if an internal standard is not used the ppm
scale will not be reliable. One can set the scale on the residual signal
from the solvent and in a sense this can serve as the internal standard. I
have recently been told that the resolution and overall quality of the
spectrum is much better when the sample is locked than when unlocked and
I am having some trouble understanding why this should be. Is this indeed
true and can someone explain why? I can find no reference to this in any of
my books or the library books.
Keith Brown
University of Saskatchewan
Saskatoon, Sask.
brownk@sask.usask.ca