Abstract

This study aimed to obtain the title spectra and verify the temperature dependence of δDSS of the HOD signal from D2 O of the NMR sample. However, the analysis of the collected δX data, extended by the results of other closely related measurements reported in the literature, provided important guidelines for performing routine 1 H/13 C NMR spectra in aqueous solvents externally referenced to neat liquid TMS contained in a coaxial capillary. Therefore, it is recommended that the previously proposed correction of δX data thus determined, which is mainly due to the difference in volume magnetic susceptibility χv between the sample and the external standard used, usually called the bulk magnetic susceptibility (BMS) correction, has been increased by +0.05 ppm (7%). The new value of this correction, +0.73 ppm, based on NMR experiments carried out at a standard temperature of 25°C, was confirmed in a classical approach using critically reviewed χm , χM , and ρ data for TMS, D2 O, and H2 O. The BMS correction for H2 O solutions is +0.75 ppm. Important issues concerning magnetic susceptibility measurements for D2 O and H2 O, coaxial bulb-ended inserts, and the geometry of two-tube NMR cells (shape factor αav ) are also critically discussed here, partly from a historical perspective.

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