NCJ Number
217646
Journal
Journal of Forensic Sciences Volume: 52 Issue: 2 Dated: March 2007 Pages: 330-334
Date Published
March 2007
Length
5 pages
Annotation
This study's objective was to identify more "true" dual regents that could, in a single reaction, reveal latent fingerprints with fluorescence of sufficiently intense color for viewing with the naked eye.
Abstract
The premixed solutions of ninhydrin with zinc or cadmium salts developed latent fingerprints on paper with fluorescence of sufficiently intense color to be viewed with the naked eye. The quality of prints developed in both modes was not inferior to the quality of prints developed by the two-stage process, i.e., ninhydrin followed by metal salt. Cooling the exhibits to liquid-nitrogen temperature significantly enhanced the intensity of the prints' fluorescence. Reducing their ninhydrin concentration to 0.05 percent turned the solution into a purely fluorogenic fingerprint reagent. The quality of the developed prints was similar to that obtained with the more concentrated solution. Working at lower concentrations is advantageous ecologically and economically. In the shorter wave-length domain, ninhydrin-metal salt reagents exhibited higher sensitivity than genipin, a recently reported dual reagent. Ninhydrin and metal salts were reacted with amino acid stains and with latent fingerprints on paper. The development was performed in a two-stage process, ninhydrin followed by metal salt (the common procedure) and in one stage (premixed solutions of ninhydrin and metal salt). Researchers examined color wave length and intensity, fluorescence wave length and intensity, solution stability, and the stability of the developed impressions. 5 figures and 28 references