NCJ Number
220414
Journal
Journal of Forensic Sciences Volume: 52 Issue: 5 Dated: September 2007 Pages: 1057-1062
Date Published
September 2007
Length
6 pages
Annotation
Because the mechanistic details of the reaction between fingerprint residue and the cyanoacrylate vapor produced by superglue fuming are not well understood, the current study obtained data on the molecular-level actions in the efficient development of latent fingerprints by superglue fuming.
Abstract
In the superglue fuming of a latent print, the fingerprint is contacted by the cyanoacrylate monomer in the vapor, which produces a white polymer along the ridges of the print, with virtually no polymer deposited on background areas. This provides the contrast needed for visualizing the fingerprint. The current study found that the primary components of sweat (lactate and alanine), which are also the major components of fingerprint residue, are capable of initiating polymerization of ethyl cyanoacrylate produced in the fuming of superglue. The similarity in the data supports the conclusion that both lactate and alanine grow the polymer by the same mechanism, i.e., initiation by the carboxylate functionality. By varying the pH, the polymerization process is either suppressed or enhanced. Increasing the pH or effectively lowering the concentration of hydrogen ions reduces termination, allowing for larger polymer growth. The results also indicate that water cannot be the primary initiator in this forensic technique. The polymerization of ethyl-cyanoacrylate vapor by sodium lactate or alanine solution was examined by monitoring the time dependence of the mass uptake and the characteristics of the resultant polymer molecular weight. 4 tables, 5 figures, and 6 references