Volume 32, Issue 3 (May 1987)
Photoluminescent Enhancement of Ninhydrin Developed Fingerprints by Metal Complexation: Structural Studies of Complexes Formed Between Ruhemann's Purple and Group IIb Metal Salts
Ruhemann's purple (RP), formed in the ninhydrin development of latent fingerprints, readily coordinates to a number of metal cations. The luminescent behavior of the Group IIb complexes has been used in the enhancement of fingerprints developed with ninhydrin. Spectroscopic evidence is presented which indicates that all three complexes have similar structures. The structure of the cadmium complex has been determined by X-ray diffraction and found to contain a 1:1 ratio of metal to chelating agent (RP). The properties of this complex suggest that it is the active agent in the cadmium(II) promoted photoluminescence of ninhydrin developed fingerprints. Coordinated water in the complex explains the need for moisture in the enhancement procedure.