Field demonstration of a portable flow immunosensor

Abstract

A portable biosensor known as the FAST 2000, developed by the Naval Research Laboratory (NRL) and engineered by Research International, Inc., has been field tested for effectiveness in performing on-site analyses for two selected explosives, TNT and RDX. The biosensor uses antibody recognition of analyte molecules and subsequent fluorescence detection downstream to measure contaminant levels in groundwater and soil. In field trials at military bases identified by the U. S. EPA as priority Superfund cleanup sites, samples containing unknown concentrations of explosives were collected from groundwater monitoring wells at various locations and analyzed in the NRL sensor with no sample pretreatment or concentration. Test sites included the Volunteer Army Ammunition Plant, Chattanooga, TN and Umatilla Army Depot Activity, Umatilla, OR. Field samples were analyzed on-site by the portable FAST 2000, and splits were analyzed by an independent U. S. EPA-certified laboratory with the use of HPLC SW846 Method 8330. Results demonstrated that the FAST 2000 can detect explosives in environmental samples with accuracy and precision. Statistical analyses based on regression curves comparing the FAST 2000 and HPLC methods showed a high degree of correlation, with r² values between 0.86 and 0.97. The assay system required small sample volumes (150 μl/test) and samples were analyzed in less than 3 min. The sensor was quantitative, with a method detection limit (MDL) of 10 μg/l. Beyond contaminated field samples, appropriate controls, blanks, and interferents were tested in the lab for certification and validation data requirements. Results were evaluated based on accuracy, precision, cost, time, and waste generation. © 1998 John Wiley & Sons, Inc. Field Analyt Chem Technol 2: 341–350, 1998