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

Abstract

Since peroxide-based explosives (PBEs) lack reactive functional groups, they cannot be determined directly by most detection methods and are often detected indirectly by converting them to H2O2. However, H2O2 may originate from many sources, causing false positives in PBE detection. Here, we developed a novel electrochemical sensor for the direct sensitive and selective determination of PBEs such as triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) using electrochemical modification of the glassy carbon (GC) electrode with PBE-memory polycarbazole (PCz) films decorated with gold nanoparticles (AuNPs) by cyclic voltammetry (CV). The prepared electrodes were named TATP-memory-GC/PCz/AuNPs (used for TATP determination) and HMTD-memory-GC/PCz/AuNPs (used for HMTD detection). The calibration lines of TATP and HMTD were found in the concentration range of 0.1–1.0 mg L–1 using the net current intensities of differential pulse voltammetry (DPV) versus analyte concentrations. The limit of detection (LOD) commonly found was 15 μg L–1 for TATP and HMTD. The sensor electrodes could separately determine intact TATP and HMTD in the presence of nitro-aromatic, nitramine, and nitrate ester energetic materials. The proposed electrochemical sensing method was not interfered by electroactive substances such as paracetamol, caffeine, acetylsalicylic acid, aspartame, d-glucose, and detergent (containing perborate and percarbonate) used as camouflage materials for PBEs. This is the first molecularly imprinted polymeric electrode for PBEs accomplishing such low LODs, and the DPV method was statistically validated in contaminated clay soil samples against the GC-MS method for TATP and a spectrophotometric method for HMTD using t- and F-tests.

The Failure of Molecular Imprinting in Conducting Polymers: A Case Study of Imprinting Picric Acid on Polycarbazole

“…The resultant polymers, after the removal of the template molecule from the polymer matrix, allow for the specific adsorption of that template, which is of great significance for producing highly selective sensors. Particular research attention has been given to molecularly imprinted conjugated polymers, such as polycarbazole or polypyrrole [ 21 , 22 , 23 ].…”

Fluorescent Photoelectric Detection of Peroxide Explosives Based on a Time Series Similarity Measurement Method

“…However, the anti-interference ability was poor, and the method was easily affected by various environmental impurities. Sa glam used PBE-memory polycarbazole films decorated with gold nanoparticles (AuNPs) via cyclic voltammetry and designed an electrochemical sensor that can directly detect TATP and HMTD, with a detection limit of 15 µg/L [13]. Pintabona used an ionization mass spectrometry method in a surface acoustic atomization environment and detected seven kinds of nitro organic explosives (in the negative ionization mode), including TNT, and the two peroxide explosives (in the positive ionization mode) TATP and HMTD [14].…”