Isoparaffinic Products
Definition
An E1618 category of ignitable liquid dominated by branched-chain (isoparaffinic) alkanes with minimal aromatic or n-alkane content. Examples include Isopar solvents and isoparaffinic paint thinners. EIP at m/z 57 shows a smooth envelope without the n-alkane picket-fence pattern.
- Classification
- ASTM E1618 ignitable liquid category
- Dominant compounds
- Branched-chain alkanes
- Example products
- Isopar solvents, isoparaffinic paint thinners
- Diagnostic ion
- m/z 57 (extracted ion profile)
Common questions
How is an isoparaffinic pattern told apart from gasoline on the m/z 57 EIP?+
Gasoline and other petroleum distillates show a picket-fence pattern of evenly spaced n-alkane peaks on the m/z 57 trace. Isoparaffinic products lack that regular n-alkane series and instead show a smooth, unresolved envelope because branched isomers dominate over straight-chain alkanes.
Why does the E1618 category matter in a fire debris report?+
Classifying a recovered ignitable liquid residue by its ASTM E1618 category, rather than naming a specific brand, lets the examiner report a defensible, standard-referenced conclusion about liquid class even when the exact product cannot be pinpointed.
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...
- DB-5 Column
- A gas chromatography capillary column with a 5% phenyl-95% dimethylpolysiloxane stationary phase, the standard column for fire debris GC-MS analysis. Provides adequate...
- 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
- In fire debris analysis, any flammable liquid that could serve as an accelerant. E1618 classifies ignitable liquids into eight categories based on...
- OSAC (Fire and Explosion)
- Organisation of Scientific Area Committees, Fire and Explosion Investigation Subcommittee, under NIST. Develops and publishes standards and needs statements for fire investigation...
- Passive Headspace Concentration (PHC)
- ASTM E1412 extraction method. The sealed evidence container is heated at 60-80°C; volatilised hydrocarbons adsorb onto an activated charcoal strip suspended in...
- SWGFEX
- Scientific Working Group for Fire and Explosion Investigation. A US-based multidisciplinary body that developed best practice guides for fire debris collection, canine...
- 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,...
- Weathering (Evaporative)
- The preferential loss of low-boiling components from an ignitable liquid by evaporation. Shifts the GC-MS pattern toward heavier components and can cause...