Explosives detection in soil using a field-portable continuous flow immunosensor

A field method for quantitative analysis of explosives in contaminated soil samples is described. The method is based on a displacement immunoassay pe rformed in a commercial instrument, the FAST 2000, engineered by Research I nternational Inc. The method can be used on-sire to measure 2,4,6-trinitrot oluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) within 5 min . For this study, replicate analyses were performed on soil extracts prepar ed from each field sample as well as appropriate controls, blanks, and labo ratory standards. Statistical analyses were done to assess accuracy, bias, and predictability of the method. The results demonstrated that the immunos ensor could be used effectively to screen environmental samples for the pre sence or absence of explosives. In most samples, the method also provided q uantitative values that were in good agreement with standard laboratory ana lyses using HPLC. A limited number of sample matrices interfered with the i mmunoassay and produced results that varied significantly from the laborato ry data. In each case, the compounds causing the problem have been identifi ed and efforts are being made to minimize these matrix interferences in fut ure field evaluations. (C) 2001 Elsevier Science B.V. All rights reserved.