Post-blast detection of explosives can involve the determination of trace levels of explosives from very di²cult matrices. Evidence submitted in such cases may include swabbings from surfaces, shrapnel, clothing, soil, automobile parts, or building materials. While methods for the detection of explosives have become increasingly selective and sensitive, when confronted with such matrices these procedures may fail due to irreversible absorption, fouling, and overload, resulting in false positive and/or false negative responses.
