Explosives Detection: From Sensing to Response

Martelo, Liliana; Marques, Lino; Berberan‐Santos, Mário Nuno

doi:10.1007/4243_2019_9

Cited by 13 publications

(14 citation statements)

References 74 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The measurement of refractive index, n, for MIPs (before TNT extraction) and NIPs represented a very good method for highlighting the imprinting effect [50]. Transmittance profiles were also proof of the auto-assembly mechanism of 1141-D monomer and TNT, which suggested that double Meisenheimer assemblies were formed and cured by polycondensation/cross-linking in the organosilica network.…”

Section: Spectroscopy Results For the Films Deposited On Glass Slidesmentioning

confidence: 92%

Biomimetic Sensitive Elements for 2,4,6-Trinitrotoluene Tested on Multi-Layered Sensors

et al. 2020

View full text Add to dashboard Cite

In spite of technological progress, most of the current techniques for 2,4,6-trinitrotoluene (TNT) detection are time consuming due to laborious sensor preparation. Thereby, the aim of this work was to enlarge the knowledge for preparing sensitive elements for TNT with the aid of molecular imprinting; a known technique used to deliver biomimetic materials. The study first depicts the auto-assembly mechanism of (TNT) with functional diamino-silanes (i.e., N-(2-aminoethyl)-3-aminopropyl methyl dimethoxysilane), via “double” Meisenheimer complexes. This mechanism is being described herein for the first time and applied further to obtain molecularly imprinted polymer (MIP) films for TNT recognition. For testing the potential application of films as chemical sensor elements, typical rebinding assays of TNT in a liquid state and the rebinding of TNT in a vapor state, using multilayered sensor chips composed of quartz-chromium (Cr)-gold (Au)-titanium oxide (TiO2), were employed. Batch rebinding experiments have shown that thinner films were more efficient on retaining TNT molecules in the first five min, with a specificity of about 1.90. The quartz-Cr-Au-TiO2-MIP capacitive sensors, tested in vapor state, registered short response times (less than 25 s), low sensitivity to humidity and high specificity for TNT.

show abstract

Section: Spectroscopy Results For the Films Deposited On Glass Slidesmentioning

confidence: 92%

Biomimetic Sensitive Elements for 2,4,6-Trinitrotoluene Tested on Multi-Layered Sensors

et al. 2020

View full text Add to dashboard Cite

show abstract

“…We employed the PEE polymer for use as an explosive sensing material based on PL quenching. It has been reported that the PL quenching of conjugated polymer by nitro-based explosives is mainly due to the photo-electron transfer, whereby the photo-excited electrons (excitons) in the LUMO states transfer to the lower-lying energy levels of the analyte molecules [ 5 , 9 , 13 , 15 , 31 ]. As seen in Figure 2 a, the electron affinity of the PEE polymer is smaller than that of TNT, allowing the photo-electron to transfer to TNT molecules.…”

Section: Resultsmentioning

confidence: 99%

“…The majority of casualties in modern and urban warfare are from the failed detection of improvised explosive devices (IED) [ 1 , 2 , 3 , 4 ]. Many present and past conflict zones are still littered with millions of landmines, continuing to bring havoc to the local populations, as well as preventing the further advancement of these mostly under-developed regions and nations [ 5 , 6 ]. Homeland security and border control spend an enormous amount on explosive material screening and detection [ 7 ], bringing various levels of discomfiture to passing passengers or travelers.…”

Section: Introductionmentioning

confidence: 99%

Influence of Air Flow on Luminescence Quenching in Polymer Films towards Explosives Detection Using Drones

Noh

Ampadu

2022

Polymers

View full text Add to dashboard Cite

Explosive detection has become an increased priority in recent years for homeland security and counter-terrorism applications. Although drones may not be able to pinpoint the exact location of the landmines and explosives, the identification of the explosive vapor present in the surrounding air provides significant information and comfort to the personnel and explosives removal equipment operators. Several optical methods, such as the luminescence quenching of fluorescent polymers, have been used for explosive detection. In order to utilize sensing technique via unmanned vehicles or drones, it is very important to study how the air flow affects the luminescence quenching. We investigated the effects of air flow on the quenching efficiency of Poly(2,5-di(2′-ethylhexyl)-1,4-ethynylene) (PEE) by TNT molecules. We treated the TNT molecules incorporated into the polymer film as non-radiative recombination centers, and found that the time derivative of the non-radiative recombination rates was greater with faster air flows. Our investigations show that relatively high air flow into an optical sensing part is crucial to achieving fast PL quenching. We also found that a “continuous light excitation” condition during the exposure of TNT vapor greatly influences the PL quenching.

show abstract

“…Because of owning electron-deficient nitro groups, NAs can complex with electron-rich groups (e.g., primary amine, aryl, and pyrenyl groups) of the designed sensors through a donor−acceptor interaction. 12 As a result, the formed complexes result in the fluorescence quenching of the designed fluorescent sensor via the mechanism of photoinduced electron transfer, 13 Forster resonance energy transfer, 13 Dexter interactions, 14 and intramolecular charge transfer. 15 The reported fluorescence sensors for sensing NAs include inorganic and organic conjugated polymers, 16 polycyclic aromatic hydrocarbon derivatives, 17 porphyrin-based compounds, 18 squaraine-related dyes, 15 semiconductor quantum dots (QDs), for example, Mn 2+ -doped ZnS, 19 CdTe, 20 and CdSe/ZnS, 21 metal nanoclusters, 22,23 and metal−organic frameworks.…”

Section: ■ Introductionmentioning

confidence: 99%

Two in One: Poly(ethyleneimine)-Modified MnO₂ Nanosheets for Ultrasensitive Detection and Catalytic Reduction of 2,4,6-Trinitrotoluene and Other Nitro Aromatics

Kumar

Tseng

2021

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

The development of a portable sensor for on-site sensing of 2, 4, 6-trinitrotoluene (TNT) and other nitro aromatics (NAs) is still needed to strengthen environmental protection and public security. Herein, we report the fabrication of fluorescent few-layered MnO 2 nanosheets (FL-MnO 2 NSs) via N,N-dimethyl formamide-mediated ultrasonication and hydrothermal treatment. Electron and spectroscopy studies demonstrate that the modification of the FL-MnO 2 NSs (named as PEI-FL-MnO 2 NSs) with amine-rich polyethyleneimine (PEI) produced planar, β-phase, well-crystalline, and positively charged nanosheets. This PEIrelated surface modification not only improves the quantum yield of the FL-MnO 2 NSs from 7.6 to 13.2% but also provides multiple binding sites with nitro groups of NAs. It was found that the presence of TNT, as an example of NAs, efficiently quenched the fluorescence of the PEI-FL-MnO 2 NSs due to the formation of Meisenheimer complexes through the efficient adsorption process. In comparison to PEI-modified MnO 2 quantum dots, the PEI-FL-MnO 2 NSs exhibited relatively high sensitivity to TNT with a limit of detection of 20 pM. By depositing PEI-FL-MnO 2 NSs on a filter paper, the as-made paper sensor was capable of visualizing 10 nM TNT in drinking water and 10 μM TNT on a postal envelope through the appearance of a quenching spot under a UV lamp. Besides, the adsorbed PEI polymer enables the PEI-FL-MnO 2 NSs to electrostatically interact with citrate-capped metal nanoparticles, producing the composites for catalyzing NaBH 4 -mediated reduction of NAs. Since the PEI-FL-MnO 2 NSs possess a large surface area to capture NAs and serve as an electron acceptor for BH 4 − , the formed composites efficiently catalyze the reaction of NaBH 4 and NAs as compared to metal nanoparticles and PEI-FL-MnO 2 NSs alone.

show abstract

Explosives Detection: From Sensing to Response

Cited by 13 publications

References 74 publications

Biomimetic Sensitive Elements for 2,4,6-Trinitrotoluene Tested on Multi-Layered Sensors

Biomimetic Sensitive Elements for 2,4,6-Trinitrotoluene Tested on Multi-Layered Sensors

Influence of Air Flow on Luminescence Quenching in Polymer Films towards Explosives Detection Using Drones

Two in One: Poly(ethyleneimine)-Modified MnO₂ Nanosheets for Ultrasensitive Detection and Catalytic Reduction of 2,4,6-Trinitrotoluene and Other Nitro Aromatics

Contact Info

Product

Resources

About

Explosives Detection: From Sensing to Response

Cited by 13 publications

References 74 publications

Biomimetic Sensitive Elements for 2,4,6-Trinitrotoluene Tested on Multi-Layered Sensors

Biomimetic Sensitive Elements for 2,4,6-Trinitrotoluene Tested on Multi-Layered Sensors

Influence of Air Flow on Luminescence Quenching in Polymer Films towards Explosives Detection Using Drones

Two in One: Poly(ethyleneimine)-Modified MnO2 Nanosheets for Ultrasensitive Detection and Catalytic Reduction of 2,4,6-Trinitrotoluene and Other Nitro Aromatics

Contact Info

Product

Resources

About

Two in One: Poly(ethyleneimine)-Modified MnO₂ Nanosheets for Ultrasensitive Detection and Catalytic Reduction of 2,4,6-Trinitrotoluene and Other Nitro Aromatics