You can probably avoid this problem if you set up the acquisition
parameters for F1 correctly. In the eda menu, for the parameter NUCLEI,
select the Edit button in the F1 dimension. Then select N15 from the menu.
You will notice that the parameter SFO1 in the F1 dimension will change.
It also changes the parameter BF1 in the F1 dimension but it is not
displayed in the eda menu. It's a good idea to do this anyway because if
you have set ND0 properly, you don't have to calculate IN0 but can simply
enter a value for SW (in ppm) in the F1 dimension.
You can actually fix this up after data collection by correcting the
value for BF1 in the F1 dimension. Look what you use for BF1 in a direct
observe N15 and use that value. To do it, type 1s BF1. Enter the correct
value. Redo the referencing and it should then come out OK.
Jane
At 04:27 PM 11/5/98 -0500, you wrote:
>
>I have been attempting to set up a 1H/15N hmqc on a
>DRX-400 running xwinnmr 2.0. I did it by calling in
>the standard Bruker parameters for a 1H/13C hmqc and
>then using edasp to change the nucleus for the second
>dimension to 15N. The experiment worked but I ran
>into problems when I tried to calibrate the chemical
>shift scale for the 15N dimension. The SF value for
>the 15N dimension always sets itself back to 100MHz
>(the 13C frequency) even if I go into edp and explicitly
>set it 40.5MHz(the 15N frequency).
>Does anyone know how to work around this problem?
>
>******************************************
> Donald M. Leek
> Steacie Institute for Molecular Sciences
> National Research Council Canada
> Ottawa, Canada K1A 0R6
> phone: (613) 993-6356
> fax: (613) 952-0068
> email: leek@ned1.sims.nrc.ca
>******************************************
>
>
>
>
Dr. Jane Strouse
Dept. of Chemistry and Biochemistry
UCLA
Los Angeles, CA 90095-1569
(310)-825-9841 - voice
(310)-825-0393 - FAX
strousej@chem.ucla.edu