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  Home > JCE Print > Journal of Chemical Education > Issues > 2005  > July  >
In the Laboratory
Simplex Optimization of Headspace-Enrichment Conditions of Residual Petroleum Distillates Used by Arsonists
Molly M. Warnke and Angela E. Erickson
Department of Chemistry, Hamline University, St. Paul, MN 55104-1284

Eugene T. Smith
Wilkes Honors College, Florida Atlantic University, Jupiter, FL 33458

Cover
July 2005
Vol. 82 No. 7
p. 1082
Abstract
A forensic project is described that is suitable for an undergraduate instrumental methods lab. Accelerants commonly used by arsonists are analyzed by static headspace enrichment followed by gas chromatography. The conditions used for headspace enrichment (e.g., time and temperature) are known to influence the distribution of hydrocarbons extracted from an arson sample. To minimize artifacts associated with headspace enrichment, simplex optimization was used to determine the optimal time and temperature for the various classes of common hydrocarbon accelerants. Both optimal enrichment times and temperatures were determined to be significantly lower than recommended by ASTM procedures for all accelerant classes. The time and temperature ranged from 1 hour at 55 °C for lighter fluid (class 1) to 4 hours at 90 °C for diesel fuel (class 4).
Supplement
A student handout, including pre- and post-lab questions, notes for the instructor, and simplex rules are available.
*  Download
JCE2005p1082W.pdf
More Information
*  Citation
 Warnke, Molly M.; Erickson, Angela E.; Smith, Eugene T. J. Chem. Educ. 2005 82 1082.
*  Keywords
 Analytical Chemistry; Chromatography; Forensic Chemistry; Hands-On Learning / Manipulatives; Inquiry-Based / Discovery Learning; Instrumental Methods; Laboratory Instruction; Problem Solving / Decision Making; Second-Year Undergraduate; Upper-Division Undergraduate
*  History
 Created:
Last Updated:		 May 31, 2005
June 8, 2005
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