Automated Signal Detection as Tool to Evaluate Magnetic Field Homogeneity from Fourier Transformed Proton NMR Spectra

Abstract

Off line analysis of proton nuclear magnetic resonance (NMR) spectra by computerized peak detection is used to determine the shim quality from Fourier transformed spectra. The method is designed to analyze spectra independently from any further information about the measurement. For this purpose, the number of maxima in a spectral region is determined and compared to the number of peaks identified by an automatic routine utilizing a curvature-based method. The resulting “shim quality quotient” represents a good indicator for the magnetic field homogeneity present during the measurement. This method can be applied to separated single signals as well as to entire spectral regions. Hence, its brought use as tool in automatic interpretation of NMR spectra is possible. An example is shown for an in situ proton NMR measurement of glucose mutarotation.