Direct Electrochemical Determination of Peroxide-Type Explosives Using Well-Dispersed Multi-Walled Carbon Nanotubes/Polyethyleneimine-Modified Glassy Carbon Electrodes

Abstract

The sensitive and selective determination of peroxide-based explosives (PBEs) in the field/on site is an important analytical challenge. Most methods claiming to detect PBEs are indirect, actually detecting their decomposition product, H2O2. Here, we present an electrochemical sensor for direct detection of organic peroxide explosives, that is, triacetone triperoxide (TATP) and hexamethylenetriperoxide diamine (HMTD), using well-dispersed multiwalled carbon nanotubes/polyethyleneimine (MWCNTs/PEI)-modified glassy carbon (GC) electrode, namely, GC/MWCNTs/PEI electrode. This is the first use of the conductive polyelectrolyte PEI as an electrode modifier for pristine PBE sensing. The potential range, scan rate, solvent selection, and supporting electrolyte concentration were optimized for PBEs. As a distinct advantage over other similar methods, our sensor electrode responded to intact TATP solutions in neutral medium, meaning that TATP did not interact with acids/bases that would transform it into H2O2. Calibration curves were linear in the range of 10–200 mg L–1 for TATP and 25–200 mg L–1 for HMTD. Using differential pulse voltammetry, detection limits of 1.5 mg L–1 TATP and 3.0 mg L–1 HMTD were obtained from direct electrochemical reduction in 80/20% (v/v) H2O–acetone solvent medium. Electroactive camouflage materials such as passenger belongings (e.g., sweetener, detergent, sugar, and paracetamol–caffeine-based analgesic drugs), common ions, and other explosives were shown not to interfere with the proposed method. The nonresponsive behavior of our electrode to H2O2 prevents “false positives” from other peroxide materials of everyday use. This electrochemical sensor could also detect other nitro-explosives at different potentials and was statistically validated against standard GC–MS and spectrophotometric methods.

Selective Electrochemical Detection of Explosives with Nanomaterial Based Electrodes

“…The same interaction applies to HMTD as their structures are very similar to each other and contain peroxide bonds just like TATP. The important advantages of the proposed voltammetric method are that the sensor electrode can measure the analytes at neutral pH (instead of high pH values reported by other authors, questioning analyte stability) and that the environment in which electrochemical measurements are made contains high water (80 % by volume) [33].…”

“…In other words, the voltammograms showed that the GCE modified with pristine MWCNTs provided a better performance than GCE modified with acid-functionalized MWCNTs and unmodified GCE [32]. In another study by Arman et al (2021), the well-dispersed MWCNTs in PEI solution were used for the modification of the GC electrode to prepare a new sensor electrode to enable direct and precise determination of TATP and HMTD. TATP molecules were kept in the polymer matrix as a consequence of the intermolecular interaction of polyelectrolyte molecules with the amine groups.…”

Direct Determination of Peroxide Explosives on Polycarbazole/Gold Nanoparticle-Modified Glassy Carbon Sensor Electrodes Imprinted for Molecular Recognition of TATP and HMTD

“…The direct electrochemical reduction of TATP and HMTD was carried out using the DPV method in an 80/20% (v/v) H 2 O–acetone solvent medium within the concentration range of 10–200 mg L –1 for TATP and 25–200 mg L –1 for HMTD, and the detection limits were 1.5 mg L –1 and 3.0 mg L –1 , respectively. Additionally, common ions, different types of energetic materials such as nitro-aromatic and nitramine-type explosives, and electroactive camouflage materials did not interfere with the proposed method …”

“…Additionally, common ions, different types of energetic materials such as nitro-aromatic and nitramine-type explosives, and electroactive camouflage materials did not interfere with the proposed method. 27 In this study, we prepared peroxide-based energetics memory-polycarbazole (PCz) films decorated with gold nanoparticles (AuNPs) for direct, sensitive, and selective determination of TATP and HMTD by the DPV method using cathodic peak current measurement. These sensor electrodes were prepared in two steps.…”

“…Additionally, common ions, different types of energetic materials such as nitro-aromatic and nitramine-type explosives, and electroactive camouflage materials did not interfere with the proposed method. 27 …”