Cross Polarization/Magic Angle Spinning Nuclear Magnetic Resonance (CP/MAS NMR) Spectroscopy

摘要: Standard techniques for solution-state 13C NMR seldom yield useful spectra when applied to solid samples as the signals are usually too weak and broad. However, problems with can be largely overcome by using cross polarization pulse sequences (Pines et al. 1973), broad linewidths sharpened spinning at “magic angle” of 54.7° relative magnetic field (Schaefer Stejskal 1976). The first CP/MAS spectrum wood showed a resonance band assigned lignin 1976), but there was gap several years before resolution improved sufficiently reveal detailed structural information about (Bartuska 1980). number research groups technique then increased rapidly commercial equipment became available scientists began recognize advantages being able characterize in situ.