Parallel nuclear magnetic resonance spectroscopy

Abstract

Nuclear magnetic resonance (NMR) spectroscopy is a principal analytical technique used for the structure elucidation of molecules. This Primer covers different approaches to accelerate data acquisition and increase sensitivity of NMR measurements through parallelization, enabled by hardware design and/or pulse sequence development. Starting with hardware-based methods, we discuss coupling multiple detectors to multiple samples so each detector/sample combination provides unique information. We then cover spatio-temporal encoding, which uses magnetic field gradients and frequency-selective manipulations to parallelize multidimensional acquisition and compress it into a single shot. We also consider the parallel manipulation of different magnetization reservoirs within a sample to yield new, information-rich pulse schemes using either homonuclear or multinuclear detection. The Experimentation section describes the set-up of parallel NMR techniques. Practical examples revealing improvements in speed and sensitivity offered by the parallel methods are demonstrated in Results. Examples of use of parallelization in small-molecule analysis are discussed in Applications, with experimental constraints addressed under the Limitations and optimizations and Reproducibility and data deposition sections. The most promising future developments are considered in the Outlook, where the largest gains are expected to emerge once the discussed techniques are combined. This Primer on parallel nuclear magnetic resonance describes various parallelization techniques ranging from hardware design to pulse sequence development that allow concurrent acquisition of different signals and lead to an increase in both data acquisition speeds and sensitivity when elucidating molecular structures.