Sodium trimethylsilylpropanesulfonate (DSS) is the organosilicon compound with the formula (CH)SiCHCHCHSONa.  It is the sodium salt of trimethylsilylpropanesulfonic acid.  A white, water-soluble solid, it is used as a chemical shift standard for proton NMR spectroscopy of aqueous solutions.  The chemical shift, specifically the signal for the trimethylsilyl group, is relatively insensitive to pH.
The proton spectrum of DSS also exhibits resonances at 2.91 ppm (m), 1.75 ppm (m), and 0.63 ppm (m) at an intensity of 22% of the reference resonance at 0 ppm.