A miniaturized field-portable immunosensor (FAST 2000) was field tested at
former military munitions sites for the detection and quantitation of TNT a
nd RDX in groundwater. Developed by the Naval Research Laboratory (NRL) and
engineered by Research International, Inc. (Woodinville, WA), the immunose
nsor performed on-site analysis of contaminated groundwater at three milita
ry bases identified by the U.S. Environmental Protection Agency (EPA) as pr
iority Superfund cleanup sites. The locations were Naval Submarine Base, SU
BASE Banger, Banger, WA; Umatilla Army Depot Activity, Umatilla, OR; and Na
val Surface Weapons Center, Crane, IN. The immunosensor uses an antibody as
the recognition element for the explosive molecule in a displacement assay
format. Detection of the explosive molecule contained in groundwater is co
nfirmed by an increase in fluorescence over background from the displaced c
yanine-labeled explosive analogue. At each site, groundwater samples contai
ning unknown concentrations of explosives were collected from monitoring we
lls and analyzed on-site by the portable immunosensor with no sample pretre
atment or concentration. Groundwater samples were split and shipped to an i
ndependent certified U.S. EPA laboratory for analysis using SW-846 Method 8
330 (HPLC). Statistical analysis based on linear regression curves comparin
g the immunosensor and the HPLC method showed good correlation, although si
te-dependent problems were encountered with some samples. The immunosensor
required small sample volumes (150 muL/test) and less than 3 min to analyze
samples with a method detection limit of 10 mug/L in the laboratory-spiked
samples. The results from this field demonstration show the viability of t
he immunosensor for on-site analysis of explosives to assist in environment
al remediation and monitoring efforts.