Test Sample: 50%H₂O 50%D₂O sample if possible dopped with 2mM CuSO₄ to yield a 3 Hz line width.

The success of gradient spectroscopy depends strongly on the ability to acquire a high resolution spectrum shortly after a gradient pulse. The recovery test verifies whether the adjustments of the amplifier control loop and the preemphasis are satisfactory and checks if no other instabilities are introduced by the gradient pulses.

The gradient recovery test is performed using a conventional ¹H parameter set. (the pulse program is set to pulprog preempgp2).

Set p16=5ms, d16=1s and the gradient pulse amplitude GPZ0=50.

Acquire a spectrum and adjust the phase correction parameters to obtain an absorption line shape. Now acquire a number of spectra for different values of the recovery delay using the AU program paropt by clicking xau paropt.

Answer the questions as follows:

Enter parameter to modify: d16

Enter initial parameter value: 0.0001

Enter initial increment: 0.0001

Enter final parameter value: 1

Enter # of experiments: 40

Judge the results by inspecting the initial amplitude and phase in comparison with those at the end of the series. If the gradients are working properly, then any differences should be minimal. See the file paropt.log in the processed data directory for a full listing of delay values and intensities. See spectrum

For the three axes accessory, repeat for each gradient direction.