Evidence Submission Guidelines - Minnesota Department of Public ...

Trace-Chemical Testing
UNCONTROLLED COPY WHEN PRINTED
MN BCA Forensic Science Service
Evidence Submission Guidelines
Authorized by: DAS
Issue Date: 03/14/2013
Page 27 of 48 Pages
The Trace-Chemical Testing section analyzes fire debris samples via gas chromatography mass
spectrometry (GC/MS) for the presence of ignitable liquids that may have been used to start or
accelerate a fire. The examinations performed are based on applicable ASTM International
guidelines for sample extraction, preparation and analysis. This section also analyzes chemical
unknowns: non-narcotic, non-biological materials of evidentiary value. Identification,
characterization and/or comparison of these materials is accomplished by the examination of
physical properties and/or using analytical instrumentation such as, but not limited to GC/MS,
FTIR, ion chromatography, and scanning electron microscope - energy dispersive spectrometer
(SEM-EDS).
The collection, preservation and timely transmittal of fire debris evidence are important steps in
the investigation of possible arson fires. When submitting fire debris or chemical unknowns to
the laboratory, use the following guidelines:
1. Fire debris evidence packaging – unused lined metal paint cans with tight fitting
friction lids.
a. Quart and gallon cans are preferred, but any size can be used. Keep in mind,
the amount of evidence to be collected will determine the size of the can
used.
b. Lined cans are preferred because unlined cans will rust through in a matter
of weeks (even days, in some cases).
Fig. 10.3- 1: New and clean paint-like lined metal cans with tight fitting friction lids are available from paint
wholesalers. It is beneficial to have an assortment of sizes on hand to ensure proper evidence packaging.
2. Liquid Samples – use glass bottles up to one ounce maximum in size with Teflon
lined screw caps and secure against breakage during transport.
3. Original Containers (such as gas cans)