DSS (NMR Standard)

DSS is a chemical compound used in proton- and carbon-related NMR spectroscopy as a calibration standard, similar to tetramethylsilane (TMS), but with much higher water solubility. Whereas TMS is the most common NMR standard used in organic solvents such as chloroform or benzene, DSS or its sodium salt is more often used for protein experiments in water.

The high electronegativity of the silicon atom draws negative charge away from the nine identical methyl protons. The result is a high intensity proton signal further down field (at lower chemical shift) than almost all peaks found in naturally occurring organic molecules. The resulting standard peak is easily identified as such and set to chemical shift 0.0.

DSS also exhibits a number of other characteristic peaks in the range of 0-3 ppm.