Electrochemical determination of dissolved nitrogen-containing explosives

Screen printed carbon electrodes (SPCE), produced close to industrial manufacturing processes as well as commercially available electrodes using nano-tubes and gold nano-particles (DRP-110CNT-GNP) were investigated with respect to the determination of nitroaromatic compounds like 2,4,6-trinitrotoluene (TNT) and 2,4-dinitrotoluene (DNT) in aqueous solution. Dynamic electrochemical measuring methods such as differential pulse voltammetry (DPV) and square wave voltammetry (SWV) are suited to measure traces of such compounds. The two peaks obtained can be separated clearly and assigned to the reduction of nitro groups. On bare carbon electrodes TNT and DNT could be determined in the concentration range between 1.2 ppb and 1500 ppb TNT (R2 = 0.994) with high reproducibility. The coating of commercial electrodes with carbon nano-tubes and gold nano-particles provided similar results for comparison purposes. The reproducibility of the results obtained on SPCE was demonstrated over a period of up to 1.5 years. The results were verified by gas chromatography with mass spectrometry (GC-MS).