Time since discharge of shotgun shells

Area of Science:

• Forensic Science
• Analytical Chemistry
• Trace Evidence Analysis

Background:

• Determining the time since discharge for spent shotgun shells is crucial in forensic investigations.
• Previous methods for age estimation of ammunition components have limitations.
• Understanding the degradation kinetics of combustion byproducts is key to developing new dating techniques.

Purpose of the Study:

• To develop and validate a novel technique for estimating the time since discharge of spent shotgun shells.
• To investigate the dissipation rate of naphthalene, a combustion product, within spent shells.
• To establish a reliable method for preserving and analyzing volatile compounds in ammunition for forensic purposes.

Main Methods:

• Utilized Solid Phase Microextraction (SPME) to sample the atmosphere inside spent shotgun shells.
• Analyzed absorbed compounds using Gas Chromatography-Mass Spectrometry (GC-MS).
• Monitored the decrease in naphthalene concentration over time and employed a glass vial to prevent its escape.

Main Results:

• Successfully monitored the decrease in naphthalene concentration in spent shotgun shells over a two-month period.
• Demonstrated that a glass vial effectively prevents naphthalene dissipation, preserving the sample integrity.
• Established that naphthalene levels, when analyzed with curve-fitting data, can accurately estimate time since discharge.

Conclusions:

• The developed SPME-GC-MS technique provides a viable method for estimating the time since discharge of spent shotgun shells.
• Naphthalene's predictable dissipation rate, when properly contained, serves as a reliable temporal marker.
• This method offers a valuable tool for forensic investigations requiring ammunition age determination.