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Success of Hexane-based Ninhydrin Amino Acid Reagent Processing on Various Inks and Ages of Porous Evidence

NCJ Number
192376
Journal
Journal of Forensic Identification Volume: 51 Issue: 6 Dated: November-December 2001 Pages: 581-586
Author(s)
Steve Scarborough
Date Published
November 2001
Length
6 pages
Annotation
This report describes the use of ninhydrin in a hexane base to examine numerous types and colors of inks in various ages of paper evidence.
Abstract
The most common solution for the chemical processing of porous items is ninhydrin in an acetone base. However, this reagent causes certain inks to run on evidence samples. This research processed porous paper items with ninhydrin-hexane to develop latent fingerprints and preserve the inked writing on the items. The solution could be brushed or dipped onto the evidence; brushing is the preferred method. The best results occur from placing the evidence in a humidity chamber prior to the ninhydrin treatment. In addition, the application of heat and steam from an iron is an effective accelerator of the development process. It is also traditional to photograph latent fingerprints on porous items prior to processing; the examiner should not deviate from that procedure. The ninhydrin-hexane solution was successful in both laboratory tests and actual case work and provides another alternative reagent for the processing of latent fingerprints. Photographs, footnote, author contact information, and 6 references