Quinoline Yellow WS is a mixture of organic compounds derived from the dye Quinoline Yellow SS. Owing to the presence of sulfonate groups, the WS dyes are water-soluble. It is a mixture of disulfonates, monosulfonates and trisulfonates of 2-indan-1,3-dione with a maximum absorption wavelength of 416 nm.p. 119 Wikipedia Appearance: Greenish yellow powder Chemical formula: C18H13NO5/8/11S1/2/3Na1/2/3 Molar mass: 477.38 g/mol Solubility in water: Soluble Melting point: 150 C (302 F; 423 K) (decomposes) Signal word: Warning