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

Abstract

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 (3M 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 mu M and 0.11-4.40 mu M for two different scan rates, 200 my s(-1) and 20 mV s(-1), respectively. The detection limit was 0.11 mu M. 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.