Gradient-Enhanced triple res. exp
Ingmar Sethson (ingmar@indra.chem.umu.se)
Mon, 10 Apr 95 12:11:52 +0200
Dear netters,
I would like to use the gradient-enhanced versions of the triple res. exps.
lie cbcaconh and hncacb ( as described by Muhandiram & Kay in JMR, Ser. B 103,
203-16 (1994) and I like to know if people have implemented such pulse sequences
on Bruker AMX-spectrometers. In particular I would like suggestions on the
following questions:
1. From the GE-HSQC-exp. as I got it from Bruker they achieve this echo-
anti-echo-selection by inverting both one the gradient during t1 and a subse-
quent 15N 90 deg. pulse, like:
go=2 ph31 cpd
d1 do st zd
3m ip5
3m ip5
lo to 3 times nbl
d11 wr #0 st0 zd
where NBL is set to 2 and NS=1. Then phase-cycling has to be performed by
explicit loop-commands. Also the gradient program must contain twice as
many gradients that actually are used (one for the echo and one for the
anti-echo-selection). Now to the question: Is there any other way of imple-
menting this when one can use phase-cycling in the ordinary way by defining
ph0-31 ?
2. The au-programme 'gradprog' can as far as I understand only define 10
gradients. In this case I would need 2*14 gradients. Will it work if I
manually edit the created gradprog in '/usr/u/exp/stan/nmr/lists/gp' to
achieve 28 nr of gradients ? (that is, is UXNMR using this ascii-file when
it applies the strength and shape of the gradients and is the number of
gradients arbitrary ).
I would very much appreciate if anyone have some suggestions and ideas in
this area.
ingmar
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* Ingmar Sethson *
* Dep. Org. Chem., *
* Umea University *
* S-901 87 UMEA, Sweden *
* Ph.nr. : +46-90-16 62 86 *
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