DOSY Experiments - Emory University

gt1 total length of the phase encoding gradient
gzlvl1 strength of the phase encoding gradient
pp 90 deg. hard 1 H pulse
pplvl decoupler power level for pp pulses
sspul flag for a GRD-90-GRD homospoil block
gzlvlhs gradient level for sspul
hsgt gradient duration for sspul
sspulX
flag for a GRD-90-GRD homospoil block during del to destroy
original X magnetization (using hsgt and gzlvlhs)
j1xh one-bond X-H coupling
mult
multiplicity;
1 selects CH's (doublets);
1.5 gives CH2's down, CH's and CH3's up;
0.5 enhances all protonated carbons
alt_grd flag to invert gradient sign on alternate scans (default = 'n')
lkgate_flg flag to gate the lock sampling off during gradient pulses
probe_ stores the probe name used to acquire the dosy experiment
Processing Parameters:
determines the number of components to be used in fitting the
ncomp
signal decay in DOSY when dosyproc='discrete'.
nugflag
nugcal_[1-5]
dosyproc
dosybypoints
'n' uses simple mono- or multi-exponential fitting to estimate
diffusion coefficients
'y' uses a modified Stejskal-Tanner equation in which the exponent
is replaced by a power series.
a 5-membered parameter array summarizing the results of the
calibration of non-uniform field gradients. Used if nugflag='y',
requires a preliminary NUG-calibration by the Doneshot_nugmap
sequence. The values are taken from the probe file at the time of
the data acquisition
'discrete' - invokes monoexponential fitting with dosyfit if ncomp=1,
and multiexponential fitting with the external programme SPLMOD
if ncomp>1.
'continuous' invokes processing with the external programme
CONTIN and gives a continuous distribution in the diffusion
domain.
'n' divides the spectrum into individual peaks, creating one crosspeak
for each individual peak found in the 1D spectrum 'y' performs
a diffusion fit for every point in the displayed region of the spectrum
that lies above the selected threshold.
This sequence uses the higher “resolving power” of the wide 13 C chemical shift range, while the
phase encoding and decoding step is done more effectively on the 1 H magnetization.
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