Pure shift spectra (1D or 2D) by homonuclear BB decoupling are typically accomplished by selective inversion of passive spins midway between dwell points or chunks of dwell points during acquisition and the magnetization is sampled when all the multiplet vector trajectories are at or very near their chemical shift trajectory. In the absence of such synchronous inversion, describing the chemical shift vector trajectory narrows down to (i) mathematically describing the FID in a tabular format of its component signals (Complete Reduction to Amplitude Frequency Table), and (ii) sorting the CRAFT table into sub-groups, each describing a set of vectors (i.e., multiplet signals) that precess in unison around their chemical (pure) shift (CRAFTps). A processing workflow for CRAFTps will be discussed. The CRAFTps process is generic, applicable to routinely acquired 2D NMR data and requires no special pulse sequence element. The process requires no user guidance minimizing user bias.
Author: Krish Krishnamurthy, Chempacker LLC, Co-author: Dan Iverson, Open VnmrJ Solutions LLC
Presented by Krish Krishnamurthy