5-Sulfosalicylic acid dihydrate is a sulfonated salicylic acid derivative.

Strong association with a range of metals makes 5-Sulfosalicylic acid useful as a metal scavenger.

It forms proton-transfer dye complexes with diazo compounds such as 4-(phenyldiazenyl)aniline. Proteins are precipitated upon complexation with 5-Sulfosalicylic acid, allowing qualitative analysis of the resultant turbidity formed in a sample by these complexes leaving solution.

Protein precipitation with 5-Sulfosalicylic acid has also been employed as a preparative measure for removing proteins prior to chromatographic analysis.

Minimum Assay: >99.0 %
Molecular Formula C7H6O6S.2H2O
Molecular Weight 254.22 g/mol
Melting Point: 224
Boiling Point: >120 deg C
Free salicylic acid Max. 0.04 %
Heavy metals (as Pb) Max. 10 ppm
Ignition residue (SO4) Max. 0.1 %
Insolubility in NH3 4 N Max. 0.03 %
Insolubility in ethanol 96 % vol Max. 0.1 %
Insolubility in water Max. 50 ppm
Cl (Chloride) Max. 10 ppm
Fe (Iron) Max. 10 ppm
Refractive Index: n20D ~1.65