Detection of gunshot residue particles from barrel swab by ultra-sensitive x-ray fluorescence spectrometry

Gunshot residue (GSR) plays a crucial role in the field of forensic ballistics. GSR is a vital link between the firearm and firing. By examine the GSR particles, the use of the firearm in a shooting incidence can be confirmed. The GSR present inside the barrel of a firearm commonly known as barrel swab is very important evidence to connect a firearm with the incident. The estimation of GSR present inside the barrel is generally carried out by chemical methods. Although, the elemental analysis of characteristic elements (i.e., lead, barium, and antimony) using AAS provides good result but has number of drawbacks which include sample preparation, detection limit and digestion of sample.

Herein, we have reported Energy Dispersive X-ray Fluorescence Spectrometry (ED-XRF) technique for the analysis of elements present in barrel swab. The analysis is focused on the estimation of concentration of three elements present in GSR i.e., lead, barium, and antimony even at very low concentration(ppb). Moreover, the significance is given to the improvised pistols and country made pistols for retrieving the barrel swab, because in 90% of the cases, the criminals use these weapons for the crime and yet no data of barrel swab estimation is available. The study suggested that this work could provide new insights for the easy estimation of barrel swab using ED-XRF technique.