Recovery and Analysis of Less Volatile Components for the Identification of Ignitable Liquid Residues in Fire Debris - Continuation of current NIJ-funded project (2020-DQ-BX-0003)

This proposal will address several OSAC research and development needs under the areas of ‘Fire Debris & Explosives’ and ‘Fire & Explosion Investigation.’ Specifically, we will 1) develop novel direct analysis in real time mass spectrometry (DART-MS) method to determine the profiles of less volatile components from ignitable liquids (IL) in fire debris; 2) investigate the effects of factors including substrates, burning degrees, and water; and 3) statistically evaluate the uncertainty and accuracy of chemometric methods used in making classification conclusions.   

The standard practice for the analysis of IL residues in fire debris is to determine the profiles of volatile compounds based on passive headspace extraction with activated charcoal (ASTM E1412) and GC/MS method (ASTM E1618). Our proposal is aimed at obtaining data for the polar and non-volatile fraction of IL to complement the GC/MS analysis of volatile fraction for correct identification of IL in fire debris in forensic investigation. Solid phase microextraction (SPME) and sorbent tube extraction coupled with DART-MS methods are used to analyze glycol ethers, hydrocarbons with m/z > 300, and non-volatile additives in different ILs on substrates and fire debris. Our preliminary studies indicate DART-MS is a promising technique for analyzing ILs with high sensitivity for the less volatile components, which are relatively less variable due to their lower vapor pressures under different sampling conditions. The goal is to exploit the unique capabilities of DART-MS for rapid detection of less volatile components from IL residues and its discrimination power for differentiating ILs on various substrates and fire debris samples with multivariate statistical methods. Potential marker compounds will be further evaluated by high-resolution MS, pyrolysis GC/MS, and infrared spectrometry to ensure the development of a robust and rapid DART-MS method for the identification of IL in fire debris. The method will be validated by analyzing mock case samples through partnerships with the Forensic Services Division of the Tennessee Bureau of Investigation. Anticipated outcomes include the development of analytical protocols for sample preparation and DART-MS analysis of IL, and statistical strategies for the classification of IL in fire debris. Project reports and scholarly products (e.g., peer-reviewed articles) will be produced. Training of future forensic scientists is achieved through students’ hands-on laboratory and research experience. Through the MTSU Forensic Institute for Research and Education (FIRE) training program, a training workshop in the application of DART-MS for IL analysis will be developed for both MTSU and non-MTSU students, forensic scientists, and law enforcement personnel. CA/NCF