Application of Fluorescent Zinc Oxide Quantum Dots for Gunshot Residue-based Firing Range Estimation
Ndayisaba Prudent, Pooja AhujaBackground:
Firing range estimation based on gunshot residue (GSR) is a crucial aspect of forensic ballistics, particularly in reconstructing shooting incidents. Conventional techniques depend on detecting heavy metals in primer residue, but the increasing use of lead-free ammunition has reduced their reliability, necessitating alternative approaches.
Aims:
The aim of this study is to evaluate the use of zinc oxide quantum dots (ZnO QDs) as fluorescent markers in GSR for estimating firing distances. Specific objectives include incorporating ZnO QDs into common ammunition calibers, analyzing fluorescence intensity as a function of distance, and assessing signal stability under various environmental and biological conditions.
Methods:
ZnO QDs were embedded in the propellants of 9 mm × 19 mm and 7.62 mm × 39 mm ammunition to produce fluorescent GSR. Controlled firings were performed at distances of 2.5 m, 5 m, 7.5 m, and 10 m. Fluorescence intensity was measured on targets and modeled using quadratic regression. Signal stability was tested across various surfaces and in the presence of blood, water, and environmental exposure.
Results:
The relationship between fluorescence intensity and distance followed a nonlinear trend, allowing estimation of firing distance with an error margin below 5%. Fluorescence signal remained stable across all tested surfaces and conditions, as confirmed by one-way ANOVA (
Conclusion:
This fluorescence-based technique offers a practical solution for distance estimation in forensic contexts. ZnO QDs provide both detection and quantification capabilities, making this method a reliable and field-deployable alternative for firearm discharge detection and conventional GSR analysis for both lead and lead-free ammunition.