has anybody experience about the setting up of a 1D selective tocsy using
a DANTE pulse as exciting pulse? After reading the book "100 and more NMR
experiments" (by Braun et al.) I set up the attached 1D tocsy sequence for
my AC200 Bruker spectrometer. The sequence is:
DANTE---trim-(MLEV17)n-trim-AQ (n so to make n*MLEV17 = 200 ms)
I put a 12 db attenuator between the TX and the probe, thus obtaining a 90
deg pulse 42 us long. I tested the sequence with a sucrose/D2O solution.
Selecting the anomeric proton (1') via DANTE I should expect all the
protons of the glucose moiety to appear. Unfortunately I just see a big
doublet corresponding to the excited 1' proton plus the signal of the
proton close to 1' (2'), the latter with a mixed phase (whereas in TOCSY
all peaks should have pure phases, if I am not wrong). Has anybody ever
been succesful with this experiment using an old Bruker machine? In this
case I would be glad to receive the sequence via e-mail.
Thank you all in advance.
Mauro
----SEQUENCE FOLLOWS---
ZE
1 D1
2 P6 PH6 ;START DANTE (I used P6=.7 us L0=60 D2=1.67M)
D2
L0 TO 2 TIMES UPR ;END DANTE
P5 PH5 ; TRIM PULSE ;P5=2.5M
3 (P1 PH1 P2 PH2 P1 PH1) ; MLEV17 START (Here P1=42us, P2=84us)
4 (P1 PH3 P2 PH4 P1 PH3)
LO TO 4 TIMES 2
(P1 PH1 P2 PH2 P1 PH1)
5 (P1 PH3 P2 PH4 P1 PH3)
LO TO 5 TIMES 2
6 (P1 PH1 P2 PH2 P1 PH1)
LO TO 6 TIMES 2
(P1 PH3 P2 PH4 P1 PH3)
7 (P1 PH1 P2 PH2 P1 PH1)
LO TO 7 TIMES 2
(P1 PH3 P2 PH4 P1 PH3)
8 (P1 PH1 P2 PH2 P1 PH1)
LO TO 8 TIMES 2
9 (P1 PH3 P2 PH4 P1 PH3)
LO TO 9 TIMES 2
(P2 PH2)
L6 TO 3 TIMES UPR ; (I used L6=72 so 66*42e-6*72 = about 200 ms)
P5 PH5 ; TRIM PULSE
GO=1 PH7 ; here pw=rd=0
EXIT
PH6= 1 3 3 1 0 2 2 0
PH5= 0 2 0 2 1 3 1 3
PH7= R1 R3 R3 R1 R0 R2 R2 R0
PH1= 3 1 3 1 0 2 0 2
PH2= 0 2 0 2 1 3 1 3
PH3= 1 3 1 3 2 0 2 0
PH4= 2 0 2 0 3 1 3 1
============================================
Mauro Andrea Cremonini, Ph.D.
Food Science and Technology Laboratory
University of Bologna
Via Ravennate 1020 - 47023 - Cesena - Italy
Phone: +39.0547.636106
FAX: +39.0547.382348
e-mail: mauro@carbon.foodsci.unibo.it
73 de IK4QIX
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