title: Detection of 2,4,6-trinitrotoluene in seawater using a reversed-displacement immunosensor.
abstract: Reported in this study are the experimental design and results of an immunosensor for the detection of the explosive, 2,4,6-trinitrotoluene (TNT) in seawater using a reversed-displacement format. This reversed-displacement immunosensor methodology has successfully measured TNT in seawater by direct injection, eliminating the need for preconcentration or pretreatment of samples. A microcolumn containing an Affi-Gel resin derivatized with a 2,4,6-trinitrobenzene (TNB) moiety and a fluorophore-labeled anti-TNT antibody composed the immunoassay reactive chamber. Fluorophore-labeled anti-TNT antibody was incubated with the modified Affi-Gel resin until binding equilibrium was reached. Under a constant flow, samples containing TNT were introduced into the flow stream displacing the fluorophore-labeled TNT antibody. Limits of detection were 2.5ng/mL or part-per-billion (ppb) for TNT in saline buffer and 25ppb in seawater with an analysis time of 10 min. Two anti-TNT antibodies with differing binding affinities were compared in the reversed-displacement assay format, and a correlation between affinity and detection limits was observed. Furthermore, we have demonstrated that the reversed-displacement format can be used to screen seawater samples containing TNT, remains effective after dozens of cycles, and provides significant fluorescence response before regeneration is required.
authors.affiliation: Center for Bio/Molecular Science and Engineering, US Naval Research Laboratory, CBMSE-Code 6900, 4555 Overlook Ave. SW, Washington, DC 20375-5320, USA.
authors.forename: Tiffanee M
authors.initials: TM
authors.lastname: Green
authors.forename: Paul T
authors.initials: PT
authors.lastname: Charles
authors.forename: George P
authors.initials: GP
authors.lastname: Anderson
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D000937:Antigen-Antibody Reactions; D015374:Biosensing Techniques; D004306:Dose-Response Relationship, Immunologic; D005452:Fluoresceins / Q000737:chemistry; D007118:Immunoassay; D015203:Reproducibility of Results; D012623:Seawater / Q000032:analysis* / Q000737:chemistry; D012680:Sensitivity and Specificity; D013605:T-2 Toxin / Q000276:immunology; D014303:Trinitrotoluene / Q000032:analysis* / Q000737:chemistry / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D005452:Fluoresceins; D014303:Trinitrotoluene; D013605:T-2 Toxin