Chromotropic acid disodium salt dihydrate

Off-white solid. Soluble in water. Fluorogenic reagent for analytical the detection of Ag, ClO3-, Cr, Hg, NO2-, NO32-, Ti or CH2O (formaldehyde). Quantitative determination of formaldehyde is based on the specific formation of a red coloration (peaking at 580 nm wavelength) when chromotropic acid in 75% sulfuric acid reacts with formaldehyde. May be employed as a chromogenic reagent for the quantification of dipyrone in various pharmaceutical preparations.