01-999124-00 J 0606
Dual and Dual Broadband NMR Probes Installation
9
Testing Probes on VnmrS and
UNITY
INOVA Systems
γ
H
2
Calibration
1.
Insert the appropriate ASTM sample in the probe and spin it.
2.
Enter
rtp('/vnmr/tests/gammaH2')
su
to retrieve the test parameter set to
the current experiment.
3.
Install the appropriate quarter-wavelength cable for
13
C.
4.
Tune the probe.
5.
Enter
pw=10 tpwr=46 ga
.
After determining the
13
C 90
°
pulse width, repeat this calibration by setting
pw
to
the
13
C 90
°
pulse width and
tpwr
to the power used to achieve the
13
C 90
°
pulse
width.
6.
Enter
dm='nny'
dpwr=30
d1=10 ga
.
Each spectrum shows a triplet.
7.
Analyze the results as follows:
a.
Measure the distance in Hz between the center peak and one of the outer peak
using the cursors.
b.
Use the same outer peak (either the one on the right or the one on the left) for
the measurements of both spectra.
The two measurements are used as input for the
h2cal
command which
calculates the
γ
H
2
for a given decoupler power level.
8.
Enter
h2cal
to calculate
γ
H
2
.
9.
Record the result and use it during the
13
C 90° pulse width test.
1
H Observe 90° Pulse Width
1.
Install the
1
H quarter-wavelength cable.
2.
Enter
rtp('/vnmr/tests/H1sn') su
.
3.
Tune the probe on the ethylbenzene sample.
4.
Enter
pw=5 at=1 lb=1
.
5.
Obtain the spectrum and adjust the phase for a positive signal.
6.
Determine the correct
tpwr
as follows:
a.
Enter
tpwr=50 pw=7 ga
.
b.
Enter
aph
to phase the spectrum after the acquisition is complete.
c.
Set the
pw
to twice the pw90 specification for the probe and array
tpwr
from
48 to 58.
Observe the spectra as it is collected. When the peak of interest passes
through the null and goes negative, the acquisition can be halted by entering
aa
. The
tpwr
value corresponding to the first negative spectrum should then
be used for pw90 calibrations.
7.
Expand the spectrum so that the quartet is centered on the screen with
wp=250
.
8.
Enter
ai
.
9.
Set
vs
so that the signal occupies about half the vertical size of the screen.
10. Enter
vp=50
.
11. Set up the following array for determining the pw90 for a probe:
