Murexide

Murexide is commonly used as an indicator in complexometric titrations, especially for Ca(II), Co(II), Cu(II), Ni(II), Cd(II), Pb(II), and rare earth metal ions. In these titrations, Murexide changes color when it forms a complex with metal ions, which helps in determining the endpoint of the titration. Murexide is slightly soluble in water. The solution is yellow in strong acidic conditions, reddish-purple in weak acidic conditions, and bluepurple in alkaline conditions. It is also a colorimetric reagent for calcium and rare earth metals and used in spectrophotometric analysis due to its distinct absorption properties. Murexide is used for the histochemical staining of calcium in the skeleton and to measure the dissociation rates of Eu(II)-containing cryptates. Historically, Murexide was used as a dye for textiles due to its vibrant color.