APPLICATION OF A PORTABLE IMMUNOSENSOR TO DETECT THE EXPLOSIVES TNT AND RDX IN GROUNDWATER SAMPLES

In the summer of 1995, the EPA conducted a performance evaluation of s everal commercially available test kits and two prototype biosensor de vices to determine if any of these technologies were feasible as an al ternative to the standard EPA SW-846 Method 8330 test for explosives i n aqueous samples. These on-site assays offer potential advantages in cost, assay time, and convenience over the traditional analysis via hi gh-performance liquid chromatography (HPLC). The continuous flow immun osensor (CFI) was one of the biosensors participating in this trial, w hich took place at two Superfund sites located on military bases. The CFI uses a small column filled with plastic beads containing immobiliz ed antibodies against the explosive being assayed and a fluorescent dy e-labeled explosive analog. Detection occurs when the native explosive in the sample is swept into the column and displaces some of the dye- labeled analog, which is quantified via a fluorometer. Results from th ese tests showed that the CFI could produce data comparable to HPLC wi th no significant problems with cross-reactivity of the antibodies aga inst other explosives or their breakdown products.