Noise Reduction in Solid-State NMR Spectra Using Principal Component Analysis

A noise reduction method was developed for solid-state nuclear magnetic resonance spectroscopy using multivariate analysis. Principal component analysis was first applied for cross-polarization/magic angle spinning and 13 C spin–lattice relaxation measurements of solid-state nuclear magnetic resonance array spectra. The contact time of cross-polarization/magic angle spinning and the delay time in spin−lattice relaxation measurements were continuously changed to obtain a series of spectra, which were used for noise reduction using principal component analysis. The noise reduction method successfully produced spectra with improved signal-to-noise ratios. This noise reduction method shortens the measurement time and allows for detection of components with minute signals.