A method for the quantitative determination of nitrites in gunshot residue cases

This paper describes a method for the quantitative determination of nitrites present in gunshot residues, using an ultraviolet-visible spectrophotometer routinely employed in colorimetric procedures. The method involves the quantitative formation of a chromophoric complex between the nitrites present in the extracted gunshot residue and the analytical reagents. The procedure has been found to be sensitive enough to detect sub-microgram quantities of nitrites in gunshot residues, and has been successfully employed in the determination of muzzle-to-target distances, a question asked often in forensic science cases.