As I got quite a few responses to my plea, I figured I would post a
little more thorough setup:
Hardware:
ARX-500/Aspect station running UXNMR (I think revision .3 or something
like that.) with a QNP probe
Sample is ethyl benzene (0.1%) (too dilute??)
I just read in the Bruker parameter set HCCOSW, the pulse program is:
1 ze
2 d11
3 d1 do d10
(p3 ph1):d
d0
p2 ph3
d0
d2
(p3 ph2):d (p1 ph4)
d3 d15
go=2 ph31 cpd
d11 wr #0 if #0 id0 zd
lo to 3 times td1
d2 do
exit
ph1=0
ph2=0 2 1 3
ph3=0 0 0 0 2 2 2 2
ph4=0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1
2 2 2 2 2 2 2 2 3 3 3 3 3 3 3 3
ph31=0 2 1 3 0 2 1 3 1 3 2 0 1 3 2 0
2 0 3 1 2 0 3 1 3 1 0 2 3 1 0 2
I set the following:
tl0 = 1db
dl0 = 20db
dl5 = 20db
p1 = 9u
p2 = 18u
p3 = 9u (I'm not sure what this pulse is for)
p31 = 100u
d0 = 3u
d1 = 2s
d2 = 4m
d3 = 2.6m
d11 = 30m
I set my O1 and O2 based on the 1D spectra. I haven't been doing many
scans and that might be part of the problem. What is a good balance
between S/N and experiment time? I assume that the problem is in
setting up the parameters because I am able to perform routine 1D
spectra on both proton and carbon as well as proton COSYs. The FID just
looks like noise so I did check the tuning, O1/O2/sweep widths and they
were OK. 101 and more says that the delays should be 1/(2*j) and
1/(3*j) for d2 and d3 respectively, but the default values in the bruker
parameter set were ten times smaller than what I calculated. I think
that's about all I am doing.
BoB
rlesuer@zoo.uvm.edu