Characterization of a Headspace Sampling Method with a Five Component Diesel Fuel Surrogate

Area of Science:

• Forensic Science
• Analytical Chemistry

Background:

• Passive headspace concentration using activated charcoal strips (ACSs) has limitations for fire debris analysis.
• PLOT-cryoadsorption offers potential advantages for extracting ignitable liquid (IL) residue.

Purpose of the Study:

• Investigate sampling parameters for PLOT-cryoadsorption in fire debris analysis.
• Determine the effect of flow rate and sample temperature on headspace vapor composition and distribution.

Main Methods:

• Utilized a five-component surrogate for diesel fuel.
• Analyzed headspace vapor composition and spatial distribution under varying flow rates (≤1.5 scc/min) and temperatures (60 °C–120 °C).

Main Results:

• Flow rates at or below 1.5 scc/min provided the most repeatable results.
• Higher sample temperatures (60 °C–120 °C) increased total analyte collection and favored lower-volatility components.
• Higher-volatility components moved further along the capillary and were more susceptible to breakthrough.

Conclusions:

• The surrogate mixture enabled effective, quantitative comparisons of sampling conditions.
• PLOT-cryoadsorption parameters require optimization for real-world fire debris analysis.
• Findings are translatable to the analysis of real diesel fuel.