Analytical Instrument Documents

Chenometrics is a discipline that utilizes data mining techniques, including dimensionality reduction, discrimination, visualization, and regression, to extract information from extensive sets of experimental analytical data. NMR spectroscopy, a highly quantitative and reproducible technique, allows for non-invasive analysis of chemical species with minimal sample preparation. This is particularly advantageous for data mining, as NMR spectra, including series of 1H NMR spectra of biological samples, are commonly employed as input for multivariate analysis by converting series of 1D NMR spectra into a matrix. The 'Chemospec' package in the R language for statistical computing serves as the engine for multivariate analysis. When the 'Chempspec' package is installed, the Delta software offers a seamless user interface for exploratory multivariate analysis.

Pulsed-Field Gradient Nuclear Magnetic Resonance (PFG-NMR) is utilized to analyze the self-diffusion of molecules and ions. The self-diffusion coefficient (D) in PFG-NMR is determined by recording the decay of signal intensity through a series of experiments using either Pulsed Gradient Spin Echo (PGSE) or Pulsed Gradient Stimulated Echo (PGSTE) sequences with varying gradient strengths (G). The decay of signal intensity is subsequently analyzed using curve fitting or inverse Laplace transformation methods. The Delta NMR software provides a curve analysis tool that supports the fitting of PFG-NMR data. Versions 5.3.3 and earlier of the Delta NMR software support curve fitting using a model that assumes a single self-diffusion coefficient contributing to the decay. However, starting from the Delta NMR software version 6.0 and onwards, there is support for curve fitting using the "Diffusion Analysis Multi" feature. This feature enables the analysis to account for multiple self-diffusion coefficients during the curve fitting process.

Pulsed-Field Gradient NMR (PFG-NMR) is utilized for analyzing the self-diffusion of molecules and ions, which are commonly referred to as 'particles' in this context. The translation of particles by thermal convection significantly impacts the decay curve in PFG-NMR experiments, particularly when dealing with solution and liquid samples. In cases where the convection-induced translation is substantial, the decay curve exhibits a cosine-like behavior, leading to an apparent increase in the self-diffusion coefficient compared to the actual value. Additionally, the decay curves may become distorted, occasionally resulting in the appearance of signals in negative phase. To address this convection artifact in PFG-NMR, Double Stimulated Echo (DSTE) experiments are specifically designed and employed.

Engineering Transition Metal Layers for Long Lasting Anionic Redox in Layered Sodium Manganese Oxide

A standard NMR system has one high-frequency channel and a low-frequency one, the ECZL series has a new function called the Multi Frequency Drive System.

Covalent organic nanotubes (CONTs) are one-dimensional porous frameworks constructed from organic building blocks via dynamic covalent chemistry.

"NMR Spectroscopy for Probing Functional Dynamics at Biological Interfaces" has been published from Royal Society of Chemistry. A chapter is contributed by Yusuke Nishiyama of JEOL RESONANCE Inc.

This research demonstrates the effect of Li and Ni co-doping in P2-type layered materials and suggests a new strategy of using Mn-rich cathode materials.

This primer article introduces a practical guide for setting up 1H detection solid-state NMR experiments under fast MAS conditions for small molecules.

Magic angle spinning (MAS) nuclear magnetic resonance (NMR) experiments at ultra low temperature (ULT) ( 100 K) have demonstrated clear benefits for obtaining large signal sensitivity gain and probing spin dynamics phenomena at ULT. ULT NMR is furthermore a highly promising platform for solid-state dynamic nuclear polarization (DNP). However, ULT NMR is not widely used, given limited availability of such instrumentation from commercial sources. In this paper, we present a comprehensive study of hydrated [U-C]alanine, a standard bio-solid sample, from the first commercial 14.1 Tesla NMR spectrometer equipped with a closed-cycle helium ULT-MAS system. The closed-cycle helium MAS system provides precise temperature control from 25 K to 100 K and stable MAS from 1.5 kHz to 12 kHz. The C CP-MAS NMR of [U-C]alanine showed 400% signal gain at 28 K compared with at 100 K. The large sensitivity gain results from the Boltzmann factor, radio frequency circuitry quality factor improvement, and the suppression of its methyl group rotation at ULT. We further observed that the addition of organic biradicals widely used for solid-state DNP significantly shortens the H T1 spin lattice relaxation time at ULT, without further broadening the C spectral linewidth compared to at 90 K. The mechanism of H T1 shortening is dominated by the two-electron-one-nucleus triple flip transition underlying the Cross Effect mechanism, widely relied upon to drive solid-state DNP. Our experimental observations suggest that the prospects of MAS NMR and DNP under ULT conditions established with a closed-cycle helium MAS system are bright.