On the questioned presence of fluorine in inorganic gunshot residue. Case work experience and experimental evidences

Matteo Donghi; Stefano Orsenigo; Giorgio Avantaggiato; Luigi Manna

doi:10.1016/j.forsciint.2021.110985

On the questioned presence of fluorine in inorganic gunshot residue. Case work experience and experimental evidences

Forensic Sci Int. 2021 Oct:327:110985. doi: 10.1016/j.forsciint.2021.110985. Epub 2021 Aug 28.

Authors

Matteo Donghi¹, Stefano Orsenigo², Giorgio Avantaggiato², Luigi Manna²

Affiliations

¹ Arma dei Carabinieri, Reparto Investigazioni Scientifiche di Parma, Parco Ducale 3, 43125 Parma, Italy. Electronic address: matteo.donghi@carabinieri.it.
² Arma dei Carabinieri, Reparto Investigazioni Scientifiche di Parma, Parco Ducale 3, 43125 Parma, Italy.

PMID: 34482281
DOI: 10.1016/j.forsciint.2021.110985

Abstract

According to the active ASTM E1588-20 Standard Practice for Gunshot Residue (GSR) Analysis, particles from lead-based primers classified as "characteristic of GSR" will have the chemical composition lead/antimony/barium. Further elements allowed to be incorporated into GSR are explicitly listed in the ASTM guideline. Fluorine is not considered a possible additional element as no common sources of F in shooting related activities have ever been documented. Moreover, presence of fluorine was demonstrated in GSR-similar particles produced by airbag deployments and the possibility to use F as a chemical marker to exclude any discharging of a firearm was consequently suggested. In authors' case work experience, fluorine containing particles were found on stubs collected from victims' clothes, discharged firearms and shooters' hands. Adopting a "case by case" approach, a firearm-related fluorine origin was then sought. Fluorine-based protective lubricants, used both for guns and ammunition components, were experimentally confirmed as a possible source of F in GSR.

Keywords: Fluorine; Forensic science; Gunshot residue; PTFE; Scanning electron microscopy.