Abstract: Groundwater was mixed with phosphate buffer of pH 7.4, ethanol and surfactant and analyzed by continuous-flow immunosensors CFI), combining the highly selective antibody-antigen binding interaction with the sensitivity of fluorescence spectroscopy as the signal generation mechanism. The CFI was a semi-automated system in which the groundwater was pumped through a column containing antibodies raised against the analyte which were covalently attached to small plastic beads. As the analyte passed through the antibody matrix, some of the fluorescent dye-labelled explosive analogue was displaced from the antibody in favour of binding the analyte. The two most commonly used military explosives: 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) were detected by the method and quantified fluorimetrically. Field testing of the immunosensor proved its usefulness as a faster, less expensive and portable alternative to HPLC.

Abstract: The cited methods (apparatus illustrated) have been applied in the analysis of standard explosives (e.g., 2,4,6-trinitrotoluene, dinitrotoluene and N-methyl-2,4,6,N-tetranitroaniline and other organic nitro-compounds) by using single- or dual-electrode detection. The responses of the dual-electrode detector were found to be a function of applied working potentials. The dual-electrode technique, which showed greater sensitivity than the single-electrode method, was applicable in the analysis of explosives, drugs, nitrate ester compounds, nitro-aromatics, nitro-PAH and similar such derivatives. Calibration graphs and rectilinearities of detector response for various nitro-compounds are given. Flow injection analysis - photolysis - electrochemical detection and HPLC - photolysis - electrochemical detection may be of value in organic or inorganic trace analysis.