Gunshot Residue Analysis in the Undergraduate Laboratory Using Toy Cap Guns

ABSTRACT

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.

KEYWORDS:

• forensic analysis
• GSR
• gunshot residue
• laser-induced breakdown spectroscopy
• LIBS
• spectroscopy education

ACKNOWLEDGMENTS

This work was supported in part by the Department of Chemistry and Biochemistry at Kennesaw State University; a Kennesaw State University-Center for Excellence in Teaching and Learning-Creative Activities and Research Experiences for Teams (KSU-CETL-CARET) Grant; and an Ocean Optics, Inc. Innovation in Educational Spectroscopy Grant. The authors also thank the students in Forensic Analytical Chemistry, Spring 2008, and Instrumental Analysis, Spring 2007, and Spring 2009.

Notes

Coauthors Julie Turner, Matthew B. Rosenberg, Kimberly Kammerdiener, and Susan W. Mungai were undergraduate students at the time of the research.