The addition of a magnetic field gradient to a high resolution MAS probe leads to further advances in this type of spectroscopy. Based on the broad acceptance of gradient methods in high resolution state NMR studies, it is not surprising that gradients can be of use in HR-MAS measurements, particularly since the NMR methods are adopted from the liquid state, rather than form the solid state class of methods. As in high resolution liquid state studies, the gradient is essential for removing t1 noise and is extremely helpful in coherence pathway selection.

6.1 Magic Angle Gradient Design

6.2 Setting up the magic angle gradient