impurity detectionWe evaluate the possibilities and limits of HR MAS NMR to detect and quantify side products during solid-phase synthesis, using a model system where pyroglutamate and glutamate are coupled in a well defined ratio. Resins swollen in deuterated and protonated solvent are studied. Use...
Manual or automated NMR data processing for routine workflows—Fourier transformation, calibration, peak picking, integration, multiplet analysis, solvent detection, reference selection, etc. Exclude impurity signals and artifacts Automatic alignment and attachment of 1D curves upon import for spectra Attach...
The method requires two scans to phase cycle the selective pulse applied on the solvent resonance, and the range of inhomogeneity that can be compensated is limited by the requirement to apply this selective pulse. Interestingly, when zero-quantum coherences are encoded, there is no need to use...
Even if the impurities are all segregated into the nanopores, the maximum concentration is at most four times the impurity concentration in the bulk electrolyte. This would give rise to an estimated impurity concentration of 0.04 mol kg À 1, which is insignificant compared with the charge ...
Solvent, reference, and impurity peaks were removed prior to open to the public Digital resolutions for the most of the spectra were 0.0625 Hz, 0.125 Hz, and 0.0625 Hz for the FX-90Q, GX-400, and AL-400, respectively. When peaks exist outside the standard spectral width, a wider ...
(Casu et al., 1966, 1968), had applying Nuclear Magnetic Resonance and Rotatory Optical Dispersion techniques, to DMSO solution containing CDs, where there is a strong competition with the solvent molecules by the intramolecular hydrogen bridge, showing that the glucose residues kept their ...
impurity profilingmetabolite analysisHigh performance liquid chromatography-solid phase extraction-nuclear magnetic resonance (HPLC-SPE-NMR) is a novel hyphenation technology that concentrates single chromatographic peaks to elution volumes matching those of NMR flow probes. The SPE unit facilitates the ...
The determination was carried out by reversed-phase HPLC using an isocratic solvent elution. The method was validated and found to be precise, accurate and specific; the detector response was linear over 50–150 μg/ml (EPM) and 0.1–3 μg/ml (degradation product) range of ...
The majority of the chemical shift changes are in the fast exchange regime on the NMR time scale, as observed by single weighted-average peaks containing information on the ligand-bound and ligand-free ratio. Thus, neither of these options could be exploited. Similarly, due to an elevated off...
1H and 13C NMR can be applied to obtain information on content of general functional groups (tertiary and primary carbon atoms, aromatic cores) and possible presence of olefins or water impurity (Rakhmatullin et al., 2017b). However, it has not been widely used yet for analysis of high-...