Patent ID: 7368292

Claim:
A method for identifying explosive materials, comprising the steps of: irradiating a first location and a second location of a sample suspected of having one or more target materials deposited thereon with a broadband light source emitting light in the range of 200 nm to 500 nm, said second sample location spaced apart from said first sample location, wherein the target materials comprise one or more explosive comprising materials, exclusive of liquid solvents having one or more solutes comprising explosive materials; measuring reflected light emanated from said first sample location (R 1 ) and reflected light emanated from said second sample location (R 2 ); generating a differential reflection spectrum (DRS) for said sample by calculating a normalized difference in reflectivity of said first and said second sample locations (ΔR/ R ), wherein ΔR=R 2 -R 1 is the difference of the measured reflected light from said first and said second sample locations, and wherein R =(R 1 +R 2 ) /2 is an average reflectivity of said sample; and identifying said one or more explosives or other target materials if present on said sample based on comparing said generated DRS to at least one reference DRS for said one or more explosives or other target materials.