1,3,6,8-Pyrenetetrasulfonic acid tetrasodium salt, AdipoGen Life Sciences. Chemical. CAS: 59572-10-0. Formula: C16H6Na4O12S4 . xH2O. MW: 610.43 (anhydrous basis). Synthetic Fluorescent probe and pH indicator. It fluoresces blue in acidic solutions and in acidic organelles but fluoresces green in more basic organelles. This compound is potentially useful as a coloring agent, biological stain or optical detecting reagent. It is used in water-in-oil-in-water emulsions and as a substrate for lipase activity. Spectral data: lambdaex 375nm, lambdaem 404nm in water.