Gunshot Residue Analysis in the Undergraduate Laboratory Using Toy Cap Guns

The authors developed an experiment for the undergraduate analytical or forensic chemistry laboratory in which gunshot residues (GSRs) produced from toy cap guns are analyzed by laser-induced breakdown spectroscopy (LIBS). Alternatively, the experiment is readily adaptable to any emission spectroscopy technique. This project allows students to investigate the development of a forensic method while addressing proper sampling techniques used in forensic investigations. Students were able to develop a library of blank samples, establish signal detection limits to address legal considerations for determination of false-positive and -negative error rates, and optimize an emission spectrometer.