NCJ Number
164339
Journal
Journal of Forensic Sciences Volume: 41 Issue: 3 Dated: (May 1996) Pages: 487-492
Date Published
1996
Length
6 pages
Annotation
The described experiments show that supercritical carbon dioxide can be used as a solvent for ninhydrin in the development of latent fingerprints in a one-stage process.
Abstract
Ninhydrin is a widely used reagent for the development of latent fingerprints on porous surfaces. For the past 20 years 1,1,2-trichlorotrifluoroethane (CFC113) has been used as the solvent of choice in the United Kingdom for ninhydrin because of its non-toxicity and non-flammability. With the phasing out of CFC solvents under the terms of the Montreal Protocol on the Control of Ozone Depleting Substances, the need for a suitable replacement has arisen. Supercritical carbon dioxide has been found to be a potential replacement for CFC113 in the ninhydrin process. Furthermore, the current processes are two-stage (impregnation of reagent followed by development in an oven), whereas using supercritical carbon dioxide development of fingerprints can be conducted in one stage. This process is dependent on the presence of water and acetic acid, but the addition of excessive quantities of these compounds does cause significant ridge diffusion. It should also be possible to apply 1,8-Diazafluorene-9-one (DFO) to paper evidence using the technology outlined in this article, but supercritical carbon dioxide does not constitute a "drop-in" replacement for CFC113. The size of the apparatus needed to use supercritical carbon dioxide as a solvent will limit the size of articles that can be treated. This technology shows most promise for more advanced forensic techniques, possibly involving the extraction and analysis of trace samples of illicit materials from paper evidence in supercritical media. It may also be possible to use the technique for the application of other types of fingerprint reagent. 1 table, 2 figures, and 8 references