CONTINUOUS-FLOW IMMUNOSENSOR FOR DETECTION OF EXPLOSIVES

A continuous-flow immunosensor for detection of trinitrotoluene (TNT) in aqueous solution is described. The sensor utilizes an immobilized m onoclonal antibody specific for TNT and saturated with fluorescein-lab eled antigen. When introduced into the flow stream through the column, samples containing unlabeled antigen displace the bound labeled antig en. The displaced labeled antigen is detected downstream using a fluor ometer. The displacement of labeled antigen is directly proportional t o the concentration of unlabeled antigen applied to the column over a range of 20 to 1200 ng/mL (ppb). The sensitivity is increased when sol vents (ethanol or 2-propanol) are included in the flow buffer at conce ntrations up to 25% (v/v). By use of a cyclone air sampler and a TNT v apor generator, TNT could be detected in collected samples. The flow i mmunosensor provides the means to detect trace levels of TNT with high specificity in times of less than 1 min. Such qualities make the flow immunosensor a promising low-cost alternative to explosive detection devices currently available to transportation and security industries.