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Comparison of Different Physical Developer Working Solutions - Part II: Reliability Studies

NCJ Number
236579
Journal
Journal of Forensic Identification Volume: 61 Issue: 6 Dated: November/December 2011 Pages: 640-676
Author(s)
Stephanie Houlgrave; Robert Ramotowski
Date Published
December 2011
Length
37 pages
Annotation
The objective of Part II of this research was to discuss the importance of reliability testing to determine the stability of a reagent and comparisons conducted between two different test solutions, gold chloride (AuCl3) and EDTA tetra sodium salt.
Abstract
Physical developer (PD) is a widely used chemical processing technique for the development of latent prints on dry or wetted porous surfaces. Part I of this research compared fresh and aged batches of PD working solutions using two nonionic surfactants, Synperonic N and Tween 20, and determined that PD working solutions incorporating Synperonic N had a shelf life ranging from 10 to 15 days; whereas PD working solutions incorporating Tween 20 had a shelf life of approximately two and one-half months. The objective of Part II of this research was to discuss the importance of reliability testing to determine the stability of a reagent and comparisons conducted between two different test solutions, gold chloride (AuCl3) and EDTA tetra sodium salt. This study determined that gold chloride test solutions degrade on Whatman #2 filter paper as well as in solution; whereas EDTA tetra sodium salt test solutions degrade much slower on Whatman #2 filter paper and appear to remain stable in solution. (Published Abstract)