Frank,
Why dont you use ZG30 program instead of the zgpg30. You said proton. We have a
ARX500 and dont have any problem like that.
Jim
frank.zhou_at_chemserv.chem.lsu.edu wrote:
> Dear Friends,
>
> We have a Bruker ARX300. It is about 5 years old. We have been having various
> kinds of problems with it for about one and half years.
>
> Bruker guys already came here more than 10 times to upgrade the instrument and
> fix problems. Now we still have a problem.
>
> I just did three sets of proton NMR tests. The following are the results:
>
> The results for the first set of proton tests:
> The S/N decreased when ns was 128. The S/N became much better when the ns was
> 258. The S/N decreased again when ns was 4k and became much better when ns was
> 8k.
>
> The results for the second set of proton tests:
> The results are all normal!!! The S/N increased when the ns was increased. The
> final ns was 8k.
>
> The results for the third set of proton tests:
> The S/N decreased when ns was 1k and obtained some additional peaks (out of
> phase ) around 3.3 and 7.3 ppm. The S/N became better when ns was 4k and the
> intensity of those additional peaks became much smaller. The S/N decreased and
> those additional peaks appeared again when ns was 8k.
>
> Bruker told me that this is an unresolved software bug and asked me to add a
> loop in my pulse sequences. The following is an example:
>
> The original pulse sequence:
> ;zgpg30
> ;arx-version
> ;1D sequence for X-nucleus with power-gated H-1 decoupling
> ;using 30 degree flip angle
>
> d11=30m
> d12=20u
>
> 1 ze
> 2 d12 dl6
> d1 cpd
> d11 dl5
> p1*0.33 ph1
> go=2 ph31
> wr #0
> d11 do
> exit
>
> ph1=0 2 2 0 1 3 3 1
> ph31=0 2 2 0 1 3 3 1
>
> ;tl0: transmitter power level (default)
> ;dl5: decoupler power level for CPD/BB decoupling
> ;dl6: decoupler power level for decoupling to maintain NOE
> ;p1 : 90 degree transmitter high power pulse
> ;p31: 90 degree pulse for slave timer (cpd-sequence)
> ;d1 : relaxation delay; 1-5 * T1
> ;d11: delay for disk I/O [30 msec]
> ;d12: delay for power switching [20 usec]
> ;cpd: cpd-decoupling according to sequence defined by cpdprg
>
> The modified pulse sequence by a Bruker guy:
> ;zgpg30.mod
> ;arx-version
> ;1D sequence for X-nucleus with power-gated H-1 decoupling
> ;using 30 degree flip angle
> ; modified for very long acquisitions using block accumulations
>
> d11=30m
> d12=20u
>
> 1 ze
> 2 d12
> 3 d12 dl6
> d1 cpd
> d11 dl5
> p1*0.33 ph1
> go=3 ph31
> wr #0
> lo to 2 times l2
> d11 do
> exit
>
> ph1=0 2 2 0 1 3 3 1
> ph31=0 2 2 0 1 3 3 1
>
> ;tl0: transmitter power level (default)
> ;dl5: decoupler power level for CPD/BB decoupling
> ;dl6: decoupler power level for decoupling to maintain NOE
> ;p1 : 90 degree transmitter high power pulse
> ;p31: 90 degree pulse for slave timer (cpd-sequence)
> ;d1 : relaxation delay; 1-5 * T1
> ;d11: delay for disk I/O [30 msec]
> ;d12: delay for power switching [20 usec]
> ;cpd: cpd-decoupling according to sequence defined by cpdprg
> ; total number of scan = (l2 time ns)+ds
>
> But the modified pulse sequence does not work. I wonder if you could give me
> some suggestions.
>
> By the way, I still doubt if a software bug causes our problem. The reasons are:
> (1) Sometimes the S/N increased with increasing the NS (everything is normal).
> Sometimes the S/N started to decrease when the NS=128 and sometimes the S/N
> started to decrease when the NS=1K. It is not consistent.
> (2) There is a Bruker ARX300 in the University of Tennessee at Memphis. They do
> not have this problem. The only difference between their ARX300 and our ARX300
> is that they have a 16-bit digitizer and we have a 12-bit digitizer. We all use
> SGI O2, XWINNMR 2.6 and IRIX 6.5.
>
> Thank you very much for your help.
>
> Best wishes,
>
> Frank
>
> **********************************************************************
> Zhe (Frank) Zhou, Ph.D.
> NMR Facility Manager
> Department of Chemistry, Louisiana State University
> 232 Choppin Hall, Baton Rouge, LA 70803-1804, USA
>
> Email: frank.zhou_at_chem.lsu.edu
> Office: (225)-388-3460, Lab: (225)-388-3373/(225)-388-3597
> Departmental Fax: (225)-388-3458
> http://www.chem.lsu.edu/web/facilities/FrankZhou/frank.html
> **********************************************************************
--
Jim Breeyear
University of Vermont
Chemistry Dept.
Cook Sci. Bld.
Burlington, Vt 05405
Tel: 802-656-0196
Fax: 802-656-8705
Received on Wed Oct 18 2000 - 11:22:44 MST