Passive Headspace Concentration
Definition
The ASTM E1412 method in which an activated charcoal strip is suspended in a sealed container above heated fire debris (60-80°C, 16 hours), concentrating volatile organic compounds from the headspace by adsorption. The strip is then eluted with carbon disulfide and the eluate injected into GC-MS.
- Standard
- ASTM E1412
- Adsorbent
- Activated charcoal strip
- Conditions
- 60 to 80 degrees C, about 16 hours
- Elution
- Carbon disulfide
- Detection
- GC-MS
Common questions
What advantage does passive headspace concentration have over direct headspace injection?+
The charcoal strip accumulates volatile compounds over an extended heating period, concentrating trace accelerant residues to levels a single direct headspace injection would likely miss.
What can cause a false negative with this method?+
If the debris sample is too small or diluted, or the volatile accelerant has evaporated or been consumed in the fire, the concentrated extract may still fall below the method's detection threshold.
Related terms
- ASTM E1618
- Standard Test Method for Ignitable Liquid Residues in Extracts from Fire Debris Samples by Gas Chromatography-Mass Spectrometry. The active analytical standard defining...
- Carbon Disulfide (CS2)
- The standard elution solvent for activated charcoal strips in ASTM E1412 passive headspace analysis. Selected for its low UV absorption, minimal GC-FID...
- Evaporative Weathering
- The preferential loss of volatile components (benzene, toluene, C5-C7 alkanes) from an ignitable liquid residue during and after a fire, altering the...
- Extracted Ion Profile (EIP)
- A GC-MS chromatographic display plotting only ions of a specified m/z value against retention time, effectively filtering out all compounds that do...
- Ignitable Liquid Reference Collection (ILRC)
- A database of GC-MS chromatographic data for over 1,100 ignitable liquid products maintained by the National Centre for Forensic Science at the...
- Light Petroleum Distillate (LPD)
- The ASTM E1618 ignitable liquid class covering C4-C9 aliphatic products (charcoal lighter fluid, camping fuel, some paint thinners). The class most frequently...
- Total Ion Chromatogram (TIC)
- A GC-MS chromatographic output plotting the summed intensity of all detected ions at each retention time. Provides the full-pattern overview of a...
- Tropylium Cation (M/z 91)
- The C7H7+ fragment ion produced by rearrangement of alkylbenzenes in the EI ion source of a mass spectrometer. The diagnostic ion for...
- Unresolved Complex Mixture (UCM)
- The broad hump of hundreds of co-eluting cycloalkane and isoalkane compounds in the TIC of heavy petroleum products (diesel, heavy fuel oil,...