Rapid analysis of gunshot residues with single-particle inductively coupled plasma time-of-flight mass spectrometry
The analysis of gunshot residues (GSR) is an important part of forensic studies. GSR consist of microparticles and nanoparticles that commonly contain the elements Pb, Ba, and Sb. A range of other elements may occur, including Zn, Ti, Cu, Sn, Al, Sr, and K, depending on the manufacturer and type of ammunition. Therefore, conventional sp-ICP-MS analysis is unsuitable for characterizing GSR particles in terms of multiple elements.
In this study, researchers at the University of Vienna investigated GSR from different types of ammunition using the method of sp-ICP-TOFMS (with TOFWERK’s icpTOF 2R) making use of the quasi-simultaneous acquisition of the entire mass spectrum (i.e., m/z from 6 to 278) with a time resolution of less than 50 μs. This method was found to be capable of analyzing thousands of particles per minute, thereby enabling rapid sample screening for GSR detection with minimal sample preparation. Moreover, sp-ICP-TOFMS can also be used to identify elements not considered in standard GSR particle classification protocols, opening up the possibility of multi-elemental fingerprinting of GSR particles.