Exploring Analytical Chemistry in Gunshot Residue: Innovations and Obstacles in Organic and Inorganic Analysis

This review highlighted an overview of the techniques for analyzing gunshot residues (GSR) of both inorganic and organic compounds, with emphasis on the evolution of forensic firearms analysis over the crucial two decades. The scanning electron microscopy/energy-dispersive X-ray spectrometry (SEM-EDS) remains the standard for detecting inorganic gunshot residues (IGSR), which with advancements in ammunition necessitate the continuous adaptation of forensic laboratories. Meanwhile, for organic gunshot residues (OGSR), there are emerging analytical methods, particularly mass spectrometry and chromatography techniques, useful mainly for the identification of residues in ammunition that do not have (or with reduced content) of the metals traditionally identified by IGSR. Furthermore, this review discusses the limitations of current techniques, including extensive sample preparation and the destructive nature of certain analyses. The integration of different methods is crucial for providing a broader and more detailed characterization of GSR, reflecting the increasing complexity of contemporary forensic cases. Here we detail the results of approximately 80 articles published for the identification of IGSR and OGSR published during the past five decades, with comparison of the advantages and disadvantages of the techniques, being this review is a guide for future studies in the area, as well as useful to forensics experts.