The Effect of Sample Volume on Deuterium Gradient Shimming

Yesterday's post emphasized that the sample depth with respect to the probe coil has a huge effect on the success of deuterium gradient shimming. For similar reasons, the volume of the sample in the NMR tube also has a huge effect. The shimming routine will work best when the volume of the sample is similar to the volume of the sample used to create the shim map. If the volume deviates too much from that, then the shimming will be unsatisfactory. This is illustrated in the figure below where different volumes of the same sample were run. Each sample was gradient shimmed prior to acquisition.