• Insert the sample.
• Choose the solvent deuterium signal with the lock command.
• Tune and match the probehead (if required).
• Optimize the shim procedure (read a shim file with the rsh command if required).
• Record a conventional ¹H spectrum or a 1D LED spectrum.

From the above file, create a new dataset using edc or iexpno and change parmode to 2D.

Change the pulprog to ledgp2s

The following parameters are used in the pulse programs and are evaluated for the processing:

d20 the Stejskal-Tanner diffusion delay

d21 eddy-current delay

p30 gradient duration

d16 gradient recovery delay

Set the following gradient parameters:

Gradient ratios: gpz6 100(variable) , and gpz7 -17.13, and gpz8 -13.17.
Gradient Lengths: p30 1 ms and p19 1.1 ms.
Recovery delay: d16 100u.
The diffusion delay is d20 (standard value can be 150-200 ms) and the eddy current delay is d21.

ACQUISITION

Define the number of proton spectra to be acquired (for instance, set td1 to 32) and call the AU program dosy to create the gradient ramp function:

Enter first gradieny amplitude: 2
Enter final gradieny amplitude: 95
Enter number of points: 32
ram type (l/q): l
and finally, Do you want to start acquisition? and select OK or Cancel.

Use the eddosy window to set processing parameters and process the data with the xf2 and dosy2d commands. See Processing 2D DOSY experiments for more details.

Otherwhise, all 1D spectra can be visualized using the AU splitser program which splits the ser file into single fids, starting with the expno which follows the ser file. Then, all these 1D spectra can be processed in the same way using the multiefp program and analyzed using multi_integ . An automated analysis can also be performed using the setdiffparm AU program.

It is advisable to store acquisition and processing parameters (for instance, with the command wpar dosy2d all) to be used later.

A quick and semi-automated set-up procedure can be followed if a parameter set has been previously stored in the disk. Such procedure can also be executed using an AU  or a macro program.