Which technique is used to analyze gunshot residue?

The technique used to analyze gunshot residue is Scanning Electron Microscopy (SEM). This method is particularly effective because it allows for the examination of the microstructure and composition of particles at a very high resolution. When a firearm is discharged, it produces tiny particles of gunshot residue, which can be made up of elements such as lead, barium, and antimony. SEM is capable of detecting and identifying these specific particles due to its ability to analyze conductive samples with high precision.

In the context of forensic science, SEM is advantageous because it can distinguish between various types of particles and can show the elemental makeup of gunshot residue at a microscopic level. This gives forensic scientists the ability to confirm whether a suspect has recently fired a gun or was in proximity to someone who has.

Other techniques mentioned, while valuable in many forensic analyses, are not the primary choice for gunshot residue analysis. For instance, Gas Chromatography is typically used for separating and analyzing compounds that can be vaporized, which does not align with the specific analysis required for solid residue particles. Infrared Spectroscopy is more suited for molecular analysis of organic compounds rather than elemental analysis, and Mass Spectrometry, although powerful for analyzing compounds, does not provide the same direct visual analysis