Handheld device for rapid detection of lead (Pb2+) in gunshot residue for forensic application

Perovskite-based photoluminescent detection of lead particles in gunshot residue

Gunshot residue (GSR) analysis is crucial for forensic investigations of shooting incidents, but current methods are time-consuming, laborious, and provide limited spatial resolution. We introduce photoluminescent lead analysis (PL-Pb) for instant high-resolution GSR detection. Lead particles in GSR react into lead halide perovskite semiconductors that emit bright green light under ultraviolet irradiation. PL-Pb enables trace detection of GSR, including ricochet markings, bullet wipes, and combustion plumes. Our method visualizes fine details like rifling patterns and facilitates and extends shooting distance reconstructions. We find that PL-Pb is also suitable for rapid presumptive testing of shooting suspect's hands, clothes, shoes, and other relevant objects. The instant results, sensitivity, and spatial resolution of perovskite-based detection of lead-containing micro-traces offer unprecedented opportunities for forensic investigations and environmental studies on lead particles.

Towards more relevance in forensic science research and development

Many different issues have been identified in forensic science for more than 10 years. While quality management has often been suggested as a path forward, research is generally considered as an essential part of the solution. Through an overview of current forensic science research, this paper aims at evaluating if and how research answer the challenges forensic science is currently facing. While forensic related publications have massively increased over the years, approximately half of the publications were published in non-forensic sources, indicating that forensic science research tends to be led by other disciplines. Over the years, forensic science research has remained largely oriented towards methodological and technological development rather than relevance to the forensic science discipline and practice. Practical implementation of the techniques is rarely discussed from a forensic perspective, and thus research rarely move from the "proof-of-concept" stage to its utilisation in case investigation. The digital transformation also generated a massive increase of data, making it challenging to find the relevant pieces of information in the mass of "forensic" publications available on-line. Thus, we propose to refocus forensic science research on forensic fundamental and practical questions to strengthen the discipline and its impact on crime investigation and security issues. Our propositions represent an incentive to further discuss forensic science research and knowledge transmission through the definition of a common culture within the community, focusing on common fundamental knowledge such as a better understanding of the concept of trace and its case-based information content.

Conventional and advanced detection approaches of fluoride in water: a review

Fluorine is a naturally occurring element found in soil, water, food materials, and natural minerals such as fluorapatite, sellaite, and cryolite and exists as fluoride compounds with other elements because of high reactivity. The exposure of fluoride to the environment and human beings are industrial factors, food, water, and geogenic factors that impact the health of millions of human beings worldwide. Overexposure to fluoride exceeding the permissible limit (1.5 mg/l as per WHO) causes several diseases in human beings, such as teeth mottling, thyroid inflammation, dental fluorosis, skeletal fluorosis, lesions in the kidney, and other organs. To overcome the deleterious impact of fluoride, its detection at an early stage is very much required. Therefore, feeling the importance of the same, immense efforts have been made to the selective and sensitive determination of fluoride in water by numerous researchers. This review paper summarizes the various conventional methods such as spectroscopic, ion chromatography, ICP-OES, and gas chromatography-mass spectrometry, their advantages, and drawbacks leading to the development of advanced ready-to-use detection strategies such as stamartphones for on-the-spot fluoride detection. This review paper also discusses future directions, which will assist scientists in achieving a new benchmark in developing a reliable, cost-effective, and user-friendly fluoride detector.

A novel approach to detect barium in gunshot residue using a handheld device: a forensic application

The present manuscript describes an innovative handheld device for the rapid detection of barium (Ba²⁺) in Gunshot Residue (GSR) based on the use of gold nanomaterials capped with sodium malonate. The method depends on a shift in the Light Scattering Plasmon Resonance (LSPR) peak of malonate capped gold nanoparticles (AuNPs) from 526 nm to 610.5 nm, due to the carboxylate ion aggregation between the metal and the nanoparticles leading to a change in the color. Qualitative detection was realized by the change in the color, while for quantitative analysis a handheld device has been fabricated in-house. The results were then correlated with those of standard known methods such as UV-Vis Spectroscopy and Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). The results showed better correlation between the fabricated device and standard methods with R² = 0.98. It shows a linearity range from 0.01 mg mL^-1 to 5 mg mL^-1 with a Limit of Detection (LOD) of 0.2 mg mL^-1. Furthermore, GSR samples were collected from cloth piece set at different range of shooting (i.e. 1 ft to 16.40 ft) using different ammunition to detect the presence of Ba²⁺ with the help of the developed device and results were found similar to those of the known methods. The hand-held device was found to be unaffected by other interfering agents (i.e. Pb²⁺, Sb³⁺, Ca²⁺, Cu²⁺, Hg²⁺, Mg²⁺, As³⁺, Cr³⁺, etc.). The results demonstrated here shows high selectivity, sensitivity and rapid method for Ba²⁺ detection in GSR, showing its greater potentiality in future.