Tuesday, March 4, 2008
1H Chemical Shift Referencing in Aqueous Solutions
Typically one uses either dissolved TMS or the residual protons of commercially available deuterated solvents as convenient chemical shift references for solutions in organic solvents. This is not possible for aqueous solutions as TMS is not soluble in water and the 1H chemical shift of water is notoriously dependant on temperature, pH, chemical exchange etc... A common replacement for TMS for aqueous solutions is sodium 2,2-dimethyl-2-sila-pentane-5-sulfonate (DSS). The chemical shift of the three equivalent methyl groups of this compound can be set at 0 ppm.