Analytical determination of gold ions based on ranelate induced nanoparticle formation.

A ranelate ion, an old antiosteoporotic drug, readily reacts with gold(III) ions generating stable gold nanoparticles (AuNP@Ran). The reaction proceeds rapidly under green conditions and is specific for gold ions at room temperature. Their characteristic color associated with the plasmonic resonance effects allows its use in colorimetric/spectrophotometric analysis, as well as in spot test assays. In addition to the color changes, the gold nanoparticles exhibit surface enhanced Raman scattering (SERS), providing another interesting route for the analytical detection of gold ions. Because of the great simplicity, the ranelate method can be very convenient for monitoring gold ions, especially in metal extraction and hydrometallurgical processes.