Electrochemical detection of 2,4,6-trinitrotoluene on carbon nanotube modified electrode: Effect of acid functionalization

This work presents new insights on the electrocatalytic reduction of 2,4,6-trinitrotoluene (TNT) on carbon nanotubes (CNTs)-modified electrodes (multi-walled carbon nanotubes and double-walled carbon nanotubes). Cyclic voltammetry showed at least 5-fold current increase in the electrochemical reduction of TNT on GCE modified with pristine ("as received") CNTs. The improved performance was also verified after 60 s of accumulation and scanning using adsorptive stripping voltammetry, with slope values 20-fold higher. Acid functionalization removed residual metals from CNTs and reduced their surface area. Hence, the improved electrochemical response of TNT on pristine CNTs seems to be not only due to surface roughness (electroactive area) but mainly originating from residual metallic catalysts on CNTs. The modified electrode with pristine CNTs was applied for the determination of TNT residues on different surfaces contaminated with the explosive, showing its applicability for forensic investigations.