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Pyrolysis Products of Linear Alkylbenzenes Implications in Fire Debris Analysis

NCJ Number
243754
Journal
Journal of Forensic Sciences Volume: 58 Issue: 1 Dated: January 2013 Pages: 210-216
Author(s)
Patricia A. Contreras, M.F.S.; Stephen S. Houck, B.S.; William M. Davis, Ph.D.; Jorn C.-C. Yu, Ph.D.
Date Published
January 2013
Length
7 pages
Annotation
In this case report, potential interferences from an improvised fire-extinguishing agent, a dishwashing liquid, containing linear alkylbenzene sulfonates (LAS), was studied.
Abstract
The presence of linear alkylbenzenes (LABs) in the fire debris sample was identified from the summed ion profile (SIP) analysis. It was found that the LAS from dishwashing liquids produce LABs by thermal degradation. Direct pyrolysis of a LAS-containing dishwashing liquid at 300 degrees C yielded a distribution of LABs in the SIP. LABs began to break down at pyrolysis temperatures between 450 and 500 degrees C and completely break down by 800 degrees C. Observed pyrolysis breakdown products of LABs included toluene, ethylbenzene, meta-, para-, and ortho-xylenes, propylbenzene, indane, naphthalene, and 1- and 2-methylnaphthalenes. These data suggested the presence of LABs in fire debris evidence might complicate subsequent analysis because their breakdown products contained some of the target compounds common to ignitable liquid identification. Therefore, a positive determination of the presence of foreign ignitable liquids should be carefully evaluated when there is a presence of LABs in the SIP. Abstract published by arrangement with John Wiley & Sons.