Método Qualitativo para Coleta de Resíduos de Disparo de Arma de Fogo (GSR) das Mãos do Atirador e Análise Colorimétrica

Resumo

Gunshot residue (GSR) analysis is crucial in forensic investigations to determine the presence of metallic
residues on individuals suspected of firearm discharge. This study focuses on qualitative colorimetric
detection methods using sodium rhodizonate and dithio-oxamide indicators for lead, barium, and copper.
Experimental procedures involved sampling from individuals exposed to gunshot residues under controlled
conditions, using different ammunition types and initiators. The research emphasizes the importance
of acidic tartaric/sodium bitartrate buffer (pH 2.8) for optimal lead detection, enhancing ionization and
molecular transformation. Alternatively, acetic acid (pH 4.0) was employed due to buffer unavailability,
demonstrating effective colorimetric results despite reduced sensitivity compared to tartrate buffer. Results
highlighted distinct color changes: strong orange for barium and violet for lead complexes, enabling clear
differentiation during analyses. Factors influencing GSR quantity included ammunition type, firearm
caliber, and initiator composition, influencing residue accumulation and detection efficacy.