A comprehensive sample preparation scheme for accelerants in suspect arsoncases

This study represents a critical comparison of adsorbent based heated heads pace methods for the enrichment of volatiles from fire debris. A dynamic an d a static method, based on charcoal adsorption and solvent extraction are compared to the solid phase micro extraction (SPME) procedure. The SPME met hod has been optimized in respect to fiber type, sampling rime, sampling te mperature, analyte concentration and the effects of water, Collection effic iencies were evaluated for a variety of accelerant types, ranging from meth anol to diesel fuel. The minimun detectable quantity for each of the method s is within an order of magnitude for most accelerant types. We propose a t wo step method based on SPME with two different fibers. Polar and water sol uble accelerants such as ethanol and light petroleum distillates are most e ffectively enriched at low temperature on Carboxen(TM), a newly developed h igh capacity fiber which contains a carbon based adsorbent. Low volatility accelerants such as diesel fuel can be recovered on a methylpolysiloxane ty pe fiber at elevated temperature. Limitations of currently used sample prep aration methods are discussed.