The GNAT: A new tool for processing NMR data.

The GNAT (General NMR Analysis Toolbox) is a free and open-source software package for processing, visualising, and analysing NMR data. It supersedes the popular DOSY Toolbox, which has a narrower focus on diffusion NMR. Data import of most common formats from the major NMR platforms is supported, as well as a GNAT generic format.

Modelling and upscaling of transport in carbonates during dissolution: Validation and calibration with NMR experiments.

We present an experimental and numerical study of transport in carbonates during dissolution and its upscaling from the pore (∼μm) to core (∼cm) scale. For the experimental part, we use nuclear magnetic resonance (NMR) to probe molecular displacements (propagators) of an aqueous hydrochloric acid (HCl) solution through a Ketton limestone core. A series of propagator profiles are obtained at a large number of spatial points along the core at multiple time-steps during dissolution.

Unmixing the NMR spectra of similar species - vive la différence.

Diffusion-ordered spectroscopy (DOSY) is one of the most powerful methods for intact mixture analysis by NMR. However, the separation of overlapped spectra by current DOSY methods typically requires a minimum of 30% difference in diffusion coefficient. Here we present a new algorithm (OUTSCORE) that can improve the situation by almost an order of magnitude, allowing the unmixing of severely overlapped species of similar size, by combining least squares fitting with cross-talk minimisation, maximising spectral difference.

Filter diagonalization method for processing PFG NMR data.

Obtaining diffusion coefficients from PFG NMR diffusion (a.k.a DOSY) data is, in the general case, an ill-posed problem.

Decoupling two-dimensional NMR spectroscopy in both dimensions: pure shift NOESY and COSY.

An increase in the resolving power in 2D NMR spectra is obtained by collapsing 2D signals with multiplet structure into 2D singlets. This resolution gain is achieved by combining 2D experiments with pure shift techniques and covariance processing (see picture). The method should be of value in both manual and automated structure determination.

Local covariance order diffusion-ordered spectroscopy: a powerful tool for mixture analysis.

Diffusion-ordered spectroscopy (DOSY) is an important tool in NMR mixture analysis that has found use in most areas of chemistry, including organic synthesis, drug discovery, and supramolecular chemistry. Typically the aim is to disentangle the overlaid, and often overlapped, NMR spectra of individual mixture components and/or to obtain size and interaction information from their respective diffusion coefficients. The most common processing method, high-resolution DOSY, breaks down where component spectra overlap; here multivariate methods can be very effective, but only for small numbers (2-5) of components.