US Patent 7499808 - Characterizing nanoparticles in gunshot residue

http://www.freepatentsonline.com/7499808.html

Conventional methods for gunshot residue analysis can produce inaccurate results for close range firing and can require a relatively large sample size. This patent teaches a method based on scanning electron microscopy for nanoparticulate analysis of the residue to improve the accuracy of forensic results with a smaller sample. Claim 1 reads:

1. A method for analyzing gun-shot residue, the method comprising:

determining a size of at least one nanoparticle from the gun shot residue using a measurement system, wherein the size corresponds to a weapon caliber; and

computing a temperature of formation of the at least one nanoparticle based on the size of the at least one nanoparticle using an analysis application, wherein the temperature of formation corresponds to a firing distance, wherein the weapon caliber and firing distance are useful in forensic studies.