Applications of Luminescence to Fingerprintsand Trace Explosives Detection

摘要

Fingerprints and trace explosives detection requires great sensitivity,which is provided by luminescence and appropriate physical and chemical treat-ments. Ninhydrin, I ,2-indanedione and other chemicals react with the amino acidspresent in the fingerprint residue. The chemically treated samples, on which theprints are to be detected, are excited with the blue lines 476.5 and 488 nm of anArgon laser, and the sample's fluorescence is observed under orange filters. Thedetection of common explosives including trinitrotoluene (TNT) may also be car-ried out using luminescence techniques. Trace explosive and fingerprint detectionrequire sensitivity due to the minute amount of matter left and available on thesamples to be detected. Detection sensitivity can be gained by taking advantage ofluminescence techniques. To increase the sensitivity of such detection luminescentchemicals are used, and to distinguish among compounds in a mixture of explo-sives, time-resolved imaging techniques may suppress any unwanted and back-ground luminescence. Explosives are tagged with europium complexes showinglong lived luminescence (0.4 ms) and appropriate for time-resolved imaging. Theeuropium luminescence excitation utilizes a laser operating at 355 nm. Compari-son between photoluminescence fingerprints and trace explosives detection will bepresented and discussed: common difficulties will be exposed.