Semi-automatic analysis of fire debris

Area of Science:

• Forensic Science
• Analytical Chemistry

Background:

• Criminalistic samples present challenges due to unknown accelerant concentrations and diverse flammable products.
• Accurate identification of fire residues is crucial for forensic investigations.

Purpose of the Study:

• To develop an automated analytical strategy for efficient and accurate fire residue analysis.
• To address the challenges of varying accelerant concentrations and sample complexity.

Main Methods:

• Utilized photoionization detection for primary screening to determine appropriate analytical methods.
• Employed classical headspace determination and active charcoal tube absorption for volatile hydrocarbons.
• Applied automatic thermal desorption (ATD400) with a PONA column for C1-C15 hydrocarbon separation.
• Developed a method for heavy hydrocarbon (C13-C40) extraction, concentration, and analysis using pentane and an automatic carousel.
• Incorporated mass spectrometry for confirmatory identification.

Main Results:

• The strategy successfully separates and identifies volatile hydrocarbons from C1 to C15.
• Heavy hydrocarbons up to C40 are effectively extracted and analyzed.
• Database creation aids in the identification of flammable products.
• The method is suitable for low concentration samples and avoids cross-contamination.

Conclusions:

• The described analytical strategy provides a robust and automated approach to fire residue analysis.
• This method enhances the efficiency and accuracy of forensic sample examination.
• The strategy is integrated into a quality program, enabling high-throughput analysis of criminalistic samples.