Advances in Analysis of Gunshot Residue

Nontoxic ammunition: Challenges and perspectives for GSR identification

“…In 1933, the Mexico City Police Laboratory introduced the dermal nitrate or paraffin test. In this, a paraffin mold obtained from the suspect's hand was sprayed with a 0.25% solution of N,N‐diphenyl‐benzidine in concentrated sulfuric acid, which reacted with nitro‐compounds from the partially burnt and unburnt propellant particles showing a blue color (Romolo, 2019; Tagliaro et al, 2002). However, this method relies on the use of an indicator for nitrites that may generate false positives for compounds also found in fertilizers, pharmaceuticals, fingernail polish, urine, and on the hands of people after striking a match (Dalby et al, 2010; Espinoza & Thornton, 1994; Romolo & Margot, 2001).…”

Should Inorganic or Organic Gunshot Residues Be Analysed First?

“…IGSR are metallic particles formed after the vaporisation and condensation of inorganic elements mainly found in the primer mixture while OGSR are organic compounds that originate from the incomplete ignition, vaporisation, and condensation of the propellant powder [1,[3][4][5]. To date, forensic laboratories primarily analyse IGSR using scanning electron microscopy coupled to energy dispersive X-ray spectrometry (SEM/EDS) [6][7][8][9]. This highly sensitive and specific technique allows the detection of inorganic particles on a specimen and provides information on their elemental compositions and morphology [10,11].…”