Field-deployable sniffer for 2,4-dinitrotoluene detection

A field-deployable instrument has been developed to detect low-level 2,4-di nitrotoluene (2,4-DNT) vapors. The system is based on previously developed artificial nose technology and employs an array of sensory materials attach ed to the distal tips of an optical fiber bundle. Both semiselective and no nspecific, cross-reactive sensors were employed. Each sensor within the arr ay responds differentially to vapor exposure so the array's fluorescence re sponse patterns are unique for each analyte. The instrument is computationa lly "trained" to discriminate target response patterns from nontarget and b ackground environments. This detection system has been applied to detect 2, 4-DNT, an analyte commonly detected on the soil surface above buried 2,4,6- trinitrotoluene (TNT) land mines, in spiked soil and aqueous and ground sam ples. The system has been characterized and demonstrated the ability to det ect 120 ppb 2,4-DNT vapor in blind (unknown) humidified samples during a su pervised field test.