Additively Manufactured Electrodes for Simultaneous Detection of 2,4,6-Trinitrotoluene and Cyclotrimethylenetrinitramine in Postexplosive Residues and Environmental Samples

This work reports the use of a custom-made filament based on polylactic acid and graphite to construct additively manufactured working electrodes, using fused filament fabrication 3D-printing technology, to simultaneously detect the explosives 2,4,6-trinitrotoluene (TNT) and cyclotrimethylenetrinitramine (RDX). We propose a simple strategy to increase detectability that consists of an electrochemical preconcentration step (-1.3 V <i>vs</i> Ag|AgCl|KCl_(sat.) for 30 s) to reduce RDX and TNT species on the 3D-printed electrode prior a single differential pulse stripping voltammetry scan in Britton-Robinson buffer (pH = 6.0). Linear ranges of 2.5-30 μmol L^-1 and 50-500 μmol L^-1 and limit of detection (LOD) values of 0.57 and 8.67 μmol L^-1 were achieved for TNT and RDX, respectively. With this approach, it was possible to identify TNT and RDX in seawater and post-explosive samples. Recovery values (80-99%) for both compounds in tap water without a sample dilution step achieved through the standard addition method, attested the high performance of proposed method. This work highlights that 3D-printing technology is a powerful tool to construct portability and system for determining nitrocompounds in environmental and forensic applications.