5(6)-CFDA [124387-19-5]

5(6)-Carboxyfluorescein diacetateMolecular weight: 460.395(6)-CFDA is not fluorescent until deacetylated by esterase enzymes.  Since only viable cells can deacetylate 5-CFDA, it is utilized in assays of viable cellsλex = 492 nm; λem = 517 nm in 0.1 M Tris pH 8.0 (esterase)