Lecture
Van Marum Colloquium: Determining the recovery efficiency of gunshot residue with stubs
- Date
- Monday 21 October 2024
- Time
- Location
-
Gorlaeus Building
Einsteinweg 55
2333 CC Leiden - Room
- GM.4.13
Abstract
After a weapon has been fired, a cloud of particles is released together with the bullet. These particles are collectively referred to as gunshot residues (GSR). They deposit on the shooter as well as any objects or people in the vicinity. The collection and analysis of these GSR particles forms the basis of GSR analysis.
People and objects are commonly sampled with GSR stubs, aluminum pins with a conductive adhesive layer on top. Stubs are then analyzed with a scanning electron microscope coupled to an energy dispersive X-ray detector (SEM-EDX). However, to the best of our knowledge, there are no recent studies about the recovery of particles with the stubbing method.
A limiting factor for such studies is the lack of GSR standards. In order to determine the recovery of GSR on stubs, we need to know the initial amount of GSR on the sampled surface. Due to the nature of the deposition of GSR after a shooting, it is not easy, if at all possible, to know how much GSR has been deposited on a surface. There has been a study on making a standard solution of GSR particles. For such a standard solution, the concentration of GSR particles can be determined.
In our study we used a self-made GSR suspension. We have shown that such a solution can be deposited on stubs and analyzed with SEM-EDX, giving reproducible results. In addition, we deposited the solutions on cotton sheets to test the recovery efficiency of GSR on stubs, which give promising results. These experiments provide a starting point for determining the recovery of GSR from different surfaces and are an important step to evaluative reporting in GSR analysis.