Volatile organic compounds in polyethylene bags-A forensic perspective

Area of Science:

• Forensic Science
• Analytical Chemistry
• Materials Science

Background:

• Polyethylene bags are sometimes used as improvised packaging for fire debris analysis.
• Existing knowledge focuses on volatile compounds from polyethylene thermal decomposition, not unheated materials.
• Lack of data on volatile compounds present in unheated polyethylene is a significant gap.

Purpose of the Study:

• To determine if unheated polyethylene bags contain detectable volatile compounds.
• To identify the specific volatile compounds present in unheated polyethylene bags.

Main Methods:

• Analysis of 28 polyethylene bags from 9 different brands.
• Samples were analyzed using standard fire debris analysis procedures.
• Gas chromatography-mass spectrometry (GC-MS) or similar techniques implied.

Main Results:

• A distinct mixture of volatile compounds was detected in nearly all analyzed polyethylene bags.
• The primary characteristic compounds identified were n-alkanes and n-alkenes with an even number of carbon atoms.
• Other compounds like limonene and 2,2,4,6,6-pentamethylheptane were also frequently detected.

Conclusions:

• Unheated polyethylene bags contain characteristic volatile organic compounds, notably even-numbered n-alkanes and n-alkenes.
• These findings have implications for forensic investigations involving fire debris.
• The presence of these compounds must be considered when interpreting analytical results from fire debris samples packaged or composed of polyethylene.