Manchester NMR Methodology Group

Summary:
A new family of NMR experiments for mixture analysis (Relaxation-Encoded Selective TOCSY, REST) allows the extraction of component subspectra from mixtures. It uses isotropic mixing to label whole spin systems with the relaxation times (e.g. T₁, T₂) of individual spins. With this methodology relaxation can be combined with multivariate methods (such as OUTSCORE) in the analysis of complex mixtures.

Pulse sequence:
The basic structure of the pulse sequence consists of an initial generation of T₁ or T₂ relaxation-weighted single quantum coherence (either using the inversion recovery or PROJECT sequence, respectively); a selective 180^o pulse to select signals at a single chemical shift; and a final isotropic mixing sequence (here DIPSI-2 with zero-quantum coherence suppression) to transfer coherence throughout each spin system.

Downloads:
Bruker pulse sequence:
REST₁ (right click and chose 'save ... as')
REST₂ (right click and chose 'save ... as')

Experimental data:
Lager beer

Processing:
The processing of REST₁ and REST₂ experimental data is straightforward using the free and open source software package GNAT.

Reference:
Dal Poggetto, G.; Castañar, L.; Adams, R. W.; Morris, G. A.; Nilsson, M.; Chem. Commun. 53, 7461-7464, 2017.
DOI: 10.1039/C7CC03150E

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