7 MQMAS METHOD
7.4 MEASUREMENT
Use the pulse sequence prepared for the MQMAS measurement. For the 3QMAS with the
Z filter, you can use the sequence
3qmas_z.jxp
. For measurement parameters, copy the
parameters that are obtained by the adjustment in Sect. 7.3 and use them to perform the
measurement.
1.
Load the pulse sequence
mqmas_3Q_z.jxp
to the
Experiment Tool
.
2.
Set up parameters.
Copy the parameters from those obtained in Sect. 7.3 as follows.
a.
While
mqmas_3Q_z_setup.jxp
is opened, select
Experiment
－
Edit
－
Copy
Attributes
from the menu in the
Spectrometer Control
window.
b.
While
mqmas_3Q_z.jxp
is opened, select
Experiment
－
Edit
－
Paste At-
tributes
from the menu in the
Spectrometer Control
window.
The parameter of
mqmas_3Q_z_setup.jxp
is copied to
mqmas_3Q_z.jxp
.
3.
Set up
y_sweep
.
Perform the scaling processing (
Sect. 7.6.2) for the t1 axis of the MQMAS
spectrum. Therefore, it is necessary to set a wider
y_sweep
width than the line width
of the 1D spectrum. Moreover, if spinning sideband signals appear, set
y_sweep
to
an integer multiple of the rotational frequency to reduce the influence of sideband
signals and improve the sensitivity.
4.
Set up
scans
and
y_points
.
Since the MQMAS measurement has poor sensitivity, it is necessary to increase the
number of scans to accumulate. Determine the number of scans for accumulation
while adjusting the
total_time
and
y_points
in reference to the signal intensity at
the time of adjustment.
Also, for the 3QMAS measurement using 3-quantum coherence, set the number of
scans to multiples of 24.
5.
Click the
Submit
button.
The pulse occurs and the measurement starts.
When the measurement ends, the
nD Processor
window automatically opens.
7-8
NMECAXS_V50-SLD-2
