Nanoparticle based molecular spectroscopic determination of insensitive energetic material nitroguanidine and sensitive nitro-energetic materials

The increasing strategic demand for ammunition formulations in which sensitive and insensitive explosives are integrated has increased the usage of these explosives. This has increased the need for developing new approaches for rapid and effective on-site detection of explosives. In this context, the energetic substances studied within the scope of the thesis were limited to nitroguanidine (NQ) from the insensitive explosive class and Tetryl from the sensitive nitroaromatic explosive class. Methods based on the aggregation of gold nanoparticles (AuNPs) and Griess colorimetry were developed for their determination, respectively. In the first part of the thesis, AuNPs modified with uric acid (UA) were used to determine NQ. The study is based on the hydrogen bond interaction between the H-acceptor and/or donor groups of UA and the H-acceptor and/or donor groups of the target analyte NQ, resulting in the reduction of the distance between AuNPs (aggregation). In the second part of the thesis, a Griess reagent-supported colorimetric method was developed using nitrite, the degradation product of Tetryl, which is released as a result of a Fenton-like reaction catalyzed by copper oxide nanoparticles (CuONPs). After determining the appropriate experimental conditions for both studies and improving the analytical performance parameters, linear calibration equations were established. The detection limit of the AuNPs aggregation-based sensor for NQ is 0.063 mg L−1, and the detection limit of the Griess colorimetry-based method for Tetryl is 25.0 µg L−1. A series of microscopic and spectroscopic techniques were used to determine the size and morphology of the synthesized nanoparticles for both studies and to elucidate the mechanisms of the proposed methods. The effects of widely used energetic substances on the determination methods developed for NQ and Tetryl were investigated. The effect of NTO, which interfered with both developed methods by responding negatively and positively, respectively, was successfully eliminated by using appropriate analytical techniques. In addition, the interference effects of ionic species and camouflage substances on the determination methods developed for NQ and Tetryl were investigated. NQ and Tetryl were successfully extracted from synthetically contaminated soil samples. Finally, the developed spectrophotometric methods were statistically validated against the LC–MS/MS method available in the literature using contaminated soil extracts.