Ambient temperature 1H/13C NMR spectra of sodium 3-(trimethylsilyl)propane-1-sulfonate (DSS) in D2O referenced to external TMS: A discussion of these and closely related results. Corrections for the bulk magnetic susceptibility effect for aqueous NMR samples

Abstract

This study aimed to obtain the title spectra and verify the temperature dependence of δ_DSS of the HOD signal from D₂O of the NMR sample. However, the analysis of the collected δ_X data, extended by the results of other closely related measurements reported in the literature, provided important guidelines for performing routine ¹H/¹³C 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 δ_X data thus determined, which is mainly due to the difference in volume magnetic susceptibility χ_v 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 χ_m, χ_M, and ρ data for TMS, D₂O, and H₂O. The BMS correction for H₂O solutions is +0.75 ppm. Important issues concerning magnetic susceptibility measurements for D₂O and H₂O, coaxial bulb-ended inserts, and the geometry of two-tube NMR cells (shape factor α_av) are also critically discussed here, partly from a historical perspective.