HR-MAS: The Other NMR Approach to Polysaccharide Solids

Polysaccharides often exist in forms such as gels, gums, blends, solids, or highly viscous liquids that are intractable to conventional solution high-resolution NMR methods. Crossed Polarization Magic-Angle Spinning (CP-MAS) NMR has proven useful in many cases, particularly when the system is comparatively rigid or even crystalline. High Resolution Magic-Angle Spinning (HR-MAS) NMR offers an alternative which may be useful, particularly with respect to the most intransigent systems such as gels, blends, and even fresh never-dried plant or animal tissue. For example, it can provide a facile method for identifying chemical differences between native and mutant organisms or between normal and diseased tissues. Unlike CP-MAS, this method utilizes H-1 detection and therefore permits most of the classical one and two dimensional homonuclear and heteronuclear experiments. This chapter provides an introduction to this method and some specific examples of applications to polysaccharides.