Dear AMMRL group,
I am trying to set up our Varian Mercury 200 MHz spectrometer to collect a
Pt-195 spectrum. I have read the archives and tried those suggestions, but
I still can't see any peaks in the spectrum. My resulting spectrum is just
noise with a rolling baseline. Hopefully, I am missing something simple and
someone will be able to help me out.
My test sample is K2PtCl6 in D2O. Concentrations tried are 5 mM and 25 mM.
Since the receptivity of Pt-195 is 20 compared to C-13, I wouldn't think
concentration is my problem. Temperatures tried are 22C and 30C.
I am using our switchable/broadband probe. Tuning and matching to 42.9 MHz
works okay. Without a capacitor stick, the counter is at 97. With a
capacitor stick (11 pf), the counter is 21.
I am using the black quarter wave cable (37-118 MHz), but have tried other
cables.
Here are the experiment parameters which I have tried changing.
sfrq 42.917
tof -200k to 200k (42.7 to 43.1 MHz)
sw 100000 (max window)
at 0.32 to 1.5 sec
fn='n'
nt scans up to 462,000
with and without proton decoupling on HDO peak
d1 0.02 to 1 sec
pw 2 to 100 microsecond (the nonfatal ADC error is obtained when either pw,
tpwr, or gain is increased past a threshold value)
tpwr 0 to 63
gain 20 to 30
lb=0 to 35 Hz
I also played around with backward linear prediction of the fid.
What am I missing?
Thanks,
Stephanie
--------------------------------------------
Stephanie Mabry, Ph.D., Instrument Manager
University of Maryland, Baltimore County
Dept. of Chemistry and Biochemistry
1000 Hilltop Circle
Baltimore, MD 21250
office (410)455-1031
fax (410)455-2608
mabry_at_umbc.edu
Received on Tue Aug 05 2003 - 11:06:45 MST