Voltammetric analysis of luminescent markers in gunshot residues

Currently, SEM‐EDS is used to detect gunshot residue (GSR) from the presence of Ba, Pb, and Sb in the sample. However, the development of new nontoxic ammunition (NTA) has prevented conventional metals from being found. In this work, we aim to determine the presence of an inorganic luminescent chemi...

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Bibliographic Details
Published in:Journal of forensic sciences 2023-05, Vol.68 (3), p.780-789
Main Authors: Chedid, Alex Almeida, Azevedo, Larissa Silva, Silva Galaço, Ayla Roberta Borges, Casagrande, Thiago Rui, Serra, Osvaldo Antonio, Oliveira, Marcelo Firmino
Format: Article
Language:English
Subjects:
Ammunition
Aqueous solutions
Carbon
electrochemical sensors
Electrodes
Equipment costs
Firearm discharge residue
GSR
gunshot residue
luminescent markers
nontoxic ammunition
NTA
rare earth
Residues
Silver chloride
Ultraviolet radiation
Voltammetry
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Summary:Currently, SEM‐EDS is used to detect gunshot residue (GSR) from the presence of Ba, Pb, and Sb in the sample. However, the development of new nontoxic ammunition (NTA) has prevented conventional metals from being found. In this work, we aim to determine the presence of an inorganic luminescent chemical marker based on rare earth in gunshot residues using the technique of squarewave voltammetry (SWV). After firing, the luminescent complex [(Eu2Zr)(btc)3(Hbtc)0.5.6H2O], which is used as a chemical marker, can be detected under a UV lamp. An aqueous solution with 0.1 mol L−1 KCl as supporting electrolyte can be easily collected on carbon paste electrode surfaces for SWV analysis A = 100 mV, f = 10 Hz, and step potential of 5 mV are required. The luminescent marker incorporated into the carbon paste electrode showed two anodic peak currents in the region of 0.4 V (vs Ag/AgCl) and at 0.75 V (vs Ag/AgCl) and also a cathodic one in 0.4 V (vs Ag/AgCl). SEM‐EDS was able to analyze the same voltammetric results for conventional and nontoxic ammunition containing the luminescent marker. Therefore, voltammetry and SEM‐EDS are valid for detecting the new residue marker in GSR. Despite this, the electrochemical method is still more advantageous because of its low cost and lack of expensive equipment and supplies in forensic laboratories.
ISSN:0022-1198
1556-4029
DOI:10.1111/1556-4029.15236