| Abstract
| - Two primary explosives involved in groundwater contamination, 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), were detected on-site at lowppb levels with a semiautomated fiber optic biosensor.Validation of the Analyte 2000 (manufactured by ResearchInternational Inc., Woodinville, WA) for TNT and RDXdetection was performed at two Superfund sites, UmatillaArmy Depot and Naval Surface Weapons Center Crane.Samples from monitoring wells were split for analysis usingthe fiber optic biosensor on-site and using U.S. EPA SW-846 Method 8330 (reverse-phase high performanceliquid chromatography) in an offsite laboratory. The Analyte2000, a multifiber probe fluorimeter, was coupled to afluidics unit for semiautomated operation. The fiber opticbiosensor assay is based on a competitive fluorescentimmunoassay performed on the silica core of a fiber probe.From these studies, the limit of detection was determinedto be 5 μg/L for both TNT and RDX. In addition to thefield samples, extensive laboratory analyses were performedto determine cross-reactivity, matrix effects, and falsepositive/negative rates.
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