Compressed NMR: Combining compressive sampling and pure shift NMR techniques

Abstract

Historically, the resolution of multidimensional nuclear magnetic resonance (NMR) has been orders of magnitude lower than the intrinsic resolution that NMR spectrometers are capable of producing. The slowness of Nyquist sampling as well as the existence of signals as multiplets instead of singlets have been two of the main reasons for this underperformance. Fortunately, two compressive techniques have appeared that can overcome these limitations. Compressive sensing, also known as compressed sampling (CS), avoids the first limitation by exploiting the compressibility of typical NMR spectra, thus allowing sampling at sub-Nyquist rates, and pure shift techniques eliminate the second issue "compressing" multiplets into singlets. This paper explores the possibilities and challenges presented by this combination (compressed NMR). First, a description of the CS framework is given, followed by a description of the importance of combining it with the right pure shift experiment. Second, examples of compressed NMR spectra and how they can be combined with covariance methods will be shown.

Impact of Methoxy Substituents on Thermally Activated Delayed Fluorescence and Room-Temperature Phosphorescence in All-Organic Donor–Acceptor Systems

“…This is not clear using standard 1 H NMR techniques, as in Figure a, but it is revealed when removing the proton multiplicity using pure shift techniques , (Figure b) alongside variable temperature studies (Figure ). , Most of the carbon signals are also duplicated, although a few appear not to be. However, acquisition of an ultrahigh resolution 1 H– 13 C HSQC spectrum (Figure ) using recent compressive sampling techniques , confirmed that the duplicated signals have almost the same chemical shift.…”

Enhancing Compression Level for More Efficient Compressed Sensing and Other Lessons from NMR Spectroscopy

“…The simulation from Figure 1 shows this effect. The fact that PS-NMR naturally fits to the compressed sensing reconstruction has been discussed extensively by Aguilar and coworkers [35]. Importantly, while the couplings between nuclei of the same kind (i.e., homonuclear) can be removed using selective echo pulse sequence block in both direct and indirect dimensions of an NMR spectrum, the pseudo-random NUS is feasible only in the latter case.…”

Solution-state behaviour of algal mono-uronates evaluated by pure shift and compressive sampling NMR techniques

“…[18][19][20][21] A detailed account of this method can be found elsewhere. 22 Here it was possible, using this approach, to reduce the acquisition time of the 1 H- 13 C HSQC experiment (1024 increments, 2 transients per increment, 14 Hz/point) employed for the analysis of HManA and HGulA from around 80 minutes to 10 minutes. As an example, Figure 4 shows a comparison between a traditionally-acquired 1 H- 13 C HSQC (10 min) of HManA at pD 3.4, and the same experiment acquired using compressive sampling (also 10 min).…”