Hi, All -
I have a strange problem with our Bruker AC300. The chemical shift value
of the instrument is wrong. I used a sample containing TMS and CHCl3 in
CDCl3. The CHCl3 peak has a chemical shift value of 8.18ppm referenced to
the TMS peak at 0.0ppm. The frequency difference is 2454 Hz. That means
that reference frequency has to be 337.55 MHz (instead of 300.13MHZ) in
order to obtain 7.27ppm (2454/7.27=337.55). I have checked the parameters
called from a standard parameter file. Also, the same test sample was used
on our AC250. It gives correct CHCl3 chemical shift (7.27ppm). So, the
sample is fine. Does anyone have any idea what is wrong with the
instrument?
Thanks a lot.
Quincy
Univ of Georgia
Received on Wed Feb 09 2000 - 13:33:11 MST