Evaluation of the Dflex® Device for Fire Debris Analysis

Gasoline on hands: Preliminary study on collection and persistence

“…For example, gasoline traces could still be visually perceived on chromatograms up to 2 h after application for an initial amount of 500 ml and even up to 4 h with 1000 ml. By choosing the conclusion criteria based on Miller and Miller's definition of the peak area response to the theoretical limit of detection [6], a formal identification of gasoline would only be possible in samples collected directly after application for both initial amounts tested. The reader should also be aware that this preliminary study was performed without a previous optimisation of the analytical methodology for traces detection.…”

“…A passive headspace extraction and concentration of volatile compounds was carried out in an oven at 60 8C for 16 h with a DFLEX TM device (Albrayco Laboratories Inc., Cromwell, USA) composed of a strip of activated charcoal inserted between two semipermeable membranes and encapsulated in a metal frame [6]. In an attempt to standardise the adsorption conditions on the charcoal strip, a 1 dm 3 frame of metallic wire was also placed in the bag to ensure a constant inner volume during all the tests.…”

Extraction and concentration of vapors from fire debris for forensic purposes: Evaluation of the use of Radiello Passive Air Sampler

“…The Activated Charcoal Strip of the DFLEX (Diffusive Flammable Liquid Extraction) device, commonly used for fire residues sampling, is of approximately 320 mm 2 (8 mm × 20 mm, two faces) which produces an adsorbing surface of about 1090 mm 2 (cylinder of 5.8 mm × 60 mm). Studies have shown that the DFLEX saturation threshold is reached when fire debris contains between 25 and 30 L of a standard accelerant [14]. On the other hand, Radiello's saturation threshold can thus be estimated to be between 85 and 100 L.…”

“…This difference could influence the total abundance in chromatograms. However, it was decided not to adjust the volume of solvent used for the desorption in order to evaluate the performances of both devices for the conditions recommended by previous researches [7,14].…”

“…The airtight nylon bags were then sealed by a knot and placed in an oven at 60 • C for 16 h so that passive headspace extraction could occur [14]. Fig.…”