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.
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http://dx.doi.org/10.1039/c3cc46228e | DOI Listing |
Magn Reson Chem
January 2025
Nantes Université, CNRS, CEISAM UMR6230, Nantes, France.
Diffusion-ordered NMR spectroscopy (DOSY) is a powerful tool to analyse mixtures. Spatially encoded (SPEN) DOSY enables recording a full DOSY dataset in just one scan by performing spatial parallelisation of the gradient dimension. The simplest and most widely used approach to processing DOSY data is to fit each peak in the spectrum with a single or multiple exponential decay.
View Article and Find Full Text PDFAnal Chim Acta
September 2023
Univ. Lille, CNRS, UMR 8516, LASIRe, Laboratoire Avancé de Spectroscopie pour Les Intéractions La Réactivité et L'Environnement, F-59000, Lille, France.
The unmixing of multiexponential decay signals into monoexponential components using soft modelling approaches is a challenging task due to the strong correlation and complete window overlap of the profiles. To solve this problem, slicing methodologies, such as PowerSlicing, tensorize the original data matrix into a three-way data array that can be decomposed based on trilinear models providing unique solutions. Satisfactory results have been reported for different types of data, e.
View Article and Find Full Text PDFChem Commun (Camb)
March 2021
Université de Nantes, CNRS, CEISAM UMR 6230, F-44000 Nantes, France.
We show that the NMR spectra of components in a mixture can be separated using 2D data acquired in less than one second, and an algorithm that is executed in just a few seconds. This NMR unmixing method is based on spatial encoding of the translational diffusion coefficients of the mixture's components, with multivariate processing of the data. This requires a new frequency swept pulse, which is designed and implemented to obtain quadratic spacing of the spatially parallelised gradient dimension.
View Article and Find Full Text PDFNMR Biomed
December 2020
Center for Image Sciences, UMC Utrecht, Utrecht, the Netherlands.
Separating the decay signal from diffusion-weighted scans into two or more components can be challenging. The phasor technique is well established in the field of optical microscopy for visualization and separation of fluorescent dyes with different lifetimes. The use of the phasor technique for separation of diffusion-weighted decay signals was recently proposed.
View Article and Find Full Text PDFMini Rev Med Chem
June 2021
Department of Chemistry, Department of Nanoscience and Nanotechnology (DNN), College of Natural Sciences, Kyungpook National University (KNU), Taegu 41566, South Korea
Imaging agents are crucial in diagnosing diseases. Ultrasmall lanthanide oxide (LnO) nanoparticles (NPs) (Ln = Eu, Gd, and Dy) are promising materials as high-performance imaging agents because of their excellent magnetic, optical, and X-ray attenuation properties which can be applied as magnetic resonance imaging (MRI), fluorescence imaging (FI), and X-ray computed tomography (CT) agents, respectively. Ultrasmall LnO NPs (Ln = Eu, Gd, and Dy) are reviewed here.
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