title: Surface-enhanced Raman spectroscopy for the analysis of smokeless gunpowders and macroscopic gunshot residues.
abstract: Gunshot residues (GSR) result from the discharge of a firearm being a potential piece of evidence in criminal investigations. The macroscopic GSR particles are basically formed by burned and non-burned gunpowder. Motivated by the demand of trace analysis of these samples, in this paper, the use of surface-enhanced Raman scattering (SERS) was evaluated for the analysis of gunpowders and macroscopic GSR particles. Twenty-one different smokeless gunpowders were extracted with ethanol. SERS spectra were obtained from the diluted extracts using gold nanoaggregates and an excitation wavelength of 633 nm. They show mainly bands that could be assigned to the stabilizers diphenylamine and ethylcentralite present in the gunpowders. Then, macroscopic GSR particles obtained after firing two different ammunition cartridges on clothing were also measured using the same procedure. SERS allowed the detection of the particles collected with an aluminum stub from cloth targets without interferences from the adhesive carbon. The results demonstrate the great potential of SERS for the analysis of macroscopic GSR particles. Furthermore, they indicate that the grain-to-grain inhomogeneity of the gunpowders needs to be considered. Graphical Abstract SERS allows the detection of GSR particles collected with adhesive stubs from cloth targets using gold nanoaggregates and an excitation wavelength of 633 nm.
authors.affiliation: Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, University of Alcalá, Ctra. Madrid-Barcelona Km. 33.600, 28871, Alcalá de Henares, Madrid, Spain. m.lopezl@uah.es.|University Institute of Research in Police Sciences, Edificio Polivalente de Química, University of Alcalá, Ctra. Madrid-Barcelona Km. 33.600, 28871, Alcalá de Henares, Madrid, Spain. m.lopezl@uah.es.
authors.forename: María
authors.initials: M
authors.lastname: López-López
authors.affiliation: Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489, Adlershof, Berlin, Germany.
authors.forename: Virginia
authors.initials: V
authors.lastname: Merk
authors.affiliation: Department of Analytical Chemistry, Physical Chemistry and Chemical Engineering, University of Alcalá, Ctra. Madrid-Barcelona Km. 33.600, 28871, Alcalá de Henares, Madrid, Spain.|University Institute of Research in Police Sciences, Edificio Polivalente de Química, University of Alcalá, Ctra. Madrid-Barcelona Km. 33.600, 28871, Alcalá de Henares, Madrid, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: García-Ruiz
authors.affiliation: Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489, Adlershof, Berlin, Germany.
authors.forename: Janina
authors.initials: J
authors.lastname: Kneipp
mesh_terms: D000431:Ethanol / Q000737:chemistry; D053834:Explosive Agents / Q000032:analysis* / Q000737:chemistry*; D005389:Firearms / Q000145:classification; D044709:Forensic Ballistics / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013784:Textiles / Q000032:analysis
chemical_list: D053834:Explosive Agents; D000431:Ethanol; D006046:Gold
keywords: Diphenylamine; Forensic; Gunpowder; Gunshot residue; SERS