DB-5 Column
Definition
A gas chromatography capillary column with a 5% phenyl-95% dimethylpolysiloxane stationary phase, the standard column for fire debris GC-MS analysis. Provides adequate resolution of C6 to C25 petroleum components in order of increasing boiling point.
- Stationary phase
- 5% phenyl-95% dimethylpolysiloxane
- Use
- Standard column for fire debris GC-MS
- Resolves
- C6 to C25 petroleum components
- Elution order
- By increasing boiling point
Common questions
Why is a DB-5 type column the default choice for fire debris analysis rather than a more polar column?+
Its low-polarity, nonpolar-leaning phase separates hydrocarbons largely by volatility, producing the smooth, boiling-point-ordered elution pattern that ASTM E1618 pattern-recognition analysis is built around, whereas a more polar column would separate compounds partly by functional group interactions and disrupt that reference pattern matching.
What happens if a lab substitutes an equivalent-phase column from a different manufacturer for fire debris work?+
Because DB-5-equivalent columns from different vendors can have small differences in retention behavior and column bleed characteristics, labs typically validate the specific column against ASTM E1618 reference patterns before casework use rather than assuming any 5% phenyl column will reproduce results identically.
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...
- 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...
- Isoparaffinic Products
- An E1618 category of ignitable liquid dominated by branched-chain (isoparaffinic) alkanes with minimal aromatic or n-alkane content. Examples include Isopar solvents and...
- 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...