The addition of stationary phases or sample modifiers can be used to modify the separation achievable in the diffusion domain of diffusion NMR experiments or provide information on the nature of the analyte-sample modifier interaction. Unfortunately, the addition of insoluble chromatographic stationary phases can lead to line broadening and degradation in spectral resolution, largely because of differences in magnetic susceptibility between the sample and the stationary phase. High-resolution magic angle spinning (HR-MAS) techniques can be used to remove this broadening. Here, we attempt the application of HR-MAS to size-exclusion chromatographic NMR with limited success. Observed diffusion coefficients for polymer molecular weight reference standards are shown to be larger than those obtained on static samples. Further investigation reveals that under HR-MAS it is possible to obtain reasonably accurate estimates of diffusion coefficients, using either full rotor synchronisation or sophisticated pulse sequences. The requirement for restricting the sample to the centre of the MAS rotor to ensure homogeneous magnetic and RF fields is also tested. Copyright © 2016 John Wiley & Sons, Ltd.
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http://dx.doi.org/10.1002/mrc.4464 | DOI Listing |
J Chromatogr A
December 2024
HUN-REN Molecular Interactions in Separation Science Research Group, Ifjúság útja 6, H-7624 Pécs, Hungary; Department of Analytical and Environmental Chemistry and Szentágothai Research Center, University of Pécs, Ifjúság útja 6, H-7624 Pécs, Hungary; Institute of Bioanalysis, Medical Scool, University of Pécs, Szigeti út, H-7624 Pécs, Hungary. Electronic address:
Non-destructive chromatographic methods were used to determine the hold-up volumes of four self-packed columns containing embedded phosphate groups. The stationary phases are named Diol-P-C10, Diol-P-C18, Diol-P-Benzyl and Diol-P-Chol. The hydrophobicity of organic ligands bound to the phosphate group increases in the benzyl< decyl < octadecyl
Molecules
December 2024
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry & Chemical Engineering and Center of Materials Analysis, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China.
G-quadruplex (G4), an important secondary structure of nucleic acids, is polymorphic in structure. G4 monomers can associate with each other to form multimers, which show better application performance than monomers in some aspects. G4 dimers, the simplest and most widespread multimeric structures, are often used as a representative for studying multimers.
View Article and Find Full Text PDFAnal Chem
January 2025
Aix Marseille Univ, CNRS, ICR, Marseille 13013, France.
Size exclusion chromatography-gradient (SEC-Gradient) is a powerful technique to separate polymers by their chemical composition. The stationary phase is first conditioned with a gradient from adsorli to desorli, and polymer samples are injected after the gradient in SEC conditions. Since its first description in 2011 by Schollenberger and Radke, it has never been applied to block copolymers.
View Article and Find Full Text PDFActa Crystallogr F Struct Biol Commun
January 2025
Unité de Glycobiologie Structurale et Fonctionnelle (UGSF), UMR 8576 CNRS and University of Lille, Villeneuve d'Ascq, France.
Monoclonal antibodies recognizing nonprotein antigens remain largely underrepresented in our understanding of the molecular repertoire of innate and adaptive immunity. One such antibody is Mannitou, a murine IgM that recognizes paucimannosidic glycans. In this work, we report the production and purification of the recombinant antigen-binding fragment (Fab) of Mannitou IgM (Mannitou Fab) and employ a combination of biochemical and biophysical approaches to obtain its initial structural characterization.
View Article and Find Full Text PDFJ Pharm Sci
December 2024
Therapeutics Development & Supply, Janssen Research & Development, NV, a Johnson & Johnson company, Beerse, Belgium.
Small interfering RNAs (siRNAs) have emerged as a highly promising class of therapeutics, capable of effectively treating a wide range of indications, including previously challenging targets. To correctly characterize the duplex content of siRNA therapeutics, a careful design of the analytical conditions is required. This is due to the weak interactions governing the duplex formation and thermal stability of these double-stranded oligonucleotides.
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