Rapid analysis of gunshot residues with single-particle inductively coupled plasma time-of-flight mass spectrometry

Abstract

Gunshot residues (GSRs) from different types of ammunition have been characterized using a new method based on single-particle inductively coupled plasma time-of-flight mass spectrometry (sp-ICP-TOF-MS). This method can analyze thousands of particles per minute enabling rapid sample screening for GSR detection with minimal sample preparation. GSR particles are multi-elemental nanoparticles that are mainly defined by the elements lead, barium, and antimony. Sp-ICP-TOF-MS was also used to identify other elements contained in GSR particles while standard particle classification protocols do not consider the complexities of GSR compositions and can therefore miss out on valuable information. The proposed method can be used to support existing GSR detection methods, especially when lead-free, antimony-free, or tagged ammunition has been used; it also provides a possibility for multi-elemental fingerprinting of GSR particles.

Keywords: ICP-TOF-MS; ammunition; elemental fingerprints; handguns; multi-element analysis; nanoparticles.