The electrochemical reduction of trinitrotoluene on a platinum wire modified by chemisorbed acetonitrile

The electrochemical reduction of 2,4,6-trinitrotoluene (TNT) was investigated by cyclic voltammetry on a platinum electrode in aqueous sodium chloride solutions with acetonitrile containing different concentrations of TNT. The obtained cyclic voltammograms showed three distinct reduction peaks in the potential range of −0.45 to −0.8 V (vs. an Ag/AgCl (3 M KCl) reference electrode), which refer to the multi-step process of TNT reduction. The calibration curves of the dependence of the first peak current on the TNT concentration were linear in the ranges 4.4–638.4 μM and 0.11–4.40 μM for two different scan rates, 200 mV s−1 and 20 mV s−1, respectively. The detection limit was 0.11 μM. Acetonitrile chemisorption on Pt surface took place and caused thus modified platinum electrode to exhibit an electrochemically stabile behaviour. Hence, a very high reproducibility over a prolonged time and voltammetric cycling was provided for using a Pt wire that is easy to handle as a suitable material for TNT sensing. Additionally, it was confirmed by testing the acetonitrile modified Pt wire for TNT detection in river water.