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Analytical Methods Used for the Discrimination of Substances Suspected to be Bar Soap: A Preliminary Study

NCJ Number
216804
Journal
Journal of Forensic Sciences Volume: 51 Issue: 6 Dated: November 2006 Pages: 1334-1343
Author(s)
Marlo Arredondo MFS; Gerald M. LaPorte MSFS; Jeffrey D. Wilson MFS; Tyra McConnell MSFS; Douglas K. Shaffer M.S.; Marianne Stam M.S.
Date Published
November 2006
Length
10 pages
Annotation
Since recent submissions of materials at the U.S. Secret Service have included unidentified substances suspected of being chunks of bar soap posing as a chemical or biological agent sent to recipients, two separate studies were conducted that used different analytical protocols for characterizing a variety of commercial bar soaps.
Abstract
The total ion chromatograms (TIC) of 68 soaps were sufficiently different to distinguish the specimens from one another. Sampling soaps directly from the bar produced the greatest number of diagnostic peaks. In cases where the soap samples had been previously cut into pieces and subsequently exposed to an open environment, the resulting chromatographic profiles of the volatile organic compounds (VOC) were significantly diminished, i.e., smaller peak areas. Crushing the soap pieces and placing them into sealed vials yielded increased peak intensities. When comparing the chromatographic profiles of questioned and known soaps, it was found to be more important to rely on qualitative similarities and differences rather than relative peak heights, especially if the questioned soap had been exposed to an open environment. SEM/EDXA (scanning electron microscopy in conjunction with energy-dispersive X-ray) proved to be a useful method for categorizing soaps into three broad groups. Fourier transform-infrared spectroscopy differentiated some brands of commercial bar soaps, and it assisted in distinguishing these soaps from typical laundry detergents. The materials and methods used in the two studies are described in detail. 2 tables, 8 figures, and 17 references

Publication Format
Article
Correspondence
Publication Type
Report (Study/Research)
Language
English
Country
United States of America