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Selective Detection of Trinitrophenol by Amphiphilic Dimethylaminopyridine-Appended Zn(II)phthalocyanines at the Near-Infrared Region
摘要： Novel amphiphilic Zn(II)phthalocyanines (ZnPcs) peripherally substituted with four and eight dimethylaminopyridinium units (ZnPc1 and ZnPc2) were synthesized by cyclotetramerization of the corresponding phthalonitriles. The effect of aggregation and photophysical (fluorescence quantum yields and lifetimes) and photochemical (singlet oxygen generation and photodegradation under light irradiation) properties was investigated. The chemosensing ability of ZnPcs toward explosive nitroaromatic compounds was explored in aqueous medium. This study demonstrates that ZnPc1 and ZnPc2 show fluorescence quenching behavior upon interaction with different nitro analytes and show unprecedented selectivity toward 2,4,6-trinitrophenol with a limit of detection (LOD) of 0.7?1.1 ppm with a high quenching rate constant (Ksv) of 1.6?2.02 × 105. The near-infrared (NIR) fluorescence in thin films was quenched efficiently because of the photoinduced electron-transfer process through strong intermolecular π?π and electrostatic interactions. The sensing process is highly reversible and free from the interference of other commonly encountered nitro analytes. Further, experiments were performed to demonstrate the use of ZnPcs as efficient heterogeneous photocatalysts in the reduction of nitro explosives. The smart dual performance of multicharged ZnPcs in aqueous media quantifies them as attractive candidates in developing sensor materials at the NIR region and to possibly convert the toxic explosives into useful scaffolds. These results provide an interesting perspective toward elaboration of stable fluorescent systems for the selective sensing behavior of nitro explosives and their facile heterogeneous catalytic behavior in the reduction reactions.
关键词： trinitrophenol,photocatalysis,explosive detection,near-infrared,fluorescence quenching,dimethylaminopyridinium,Zn(II)phthalocyanines
更新于2025-11-21 11:08:12
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AIE active fluorescent organic nanoaggregates for selective detection of phenolic-nitroaromatic explosives and cell imaging
摘要： Development of organic nanoparticles with high fluorescence, good biocompatibility along with strong resistance to photobleaching through simple synthetic routes is important for diverse applications such as sensing and bioimaging. Herein, we present the development of a pyrene excimer nanoaggregate which shows aggregation induced emission (AIE) effect in a solvent mixture of THF and water. The pyrene based fluorescent probe, dimethyl-5-(pyren-1-ylmethyleneamino)isophthalate (5-DP) was synthesized through a simple single step condensation reaction from inexpensive reagents. The photophysical studies of nanoaggregated system further corroborates the AIE active behavior of 5-DP probe at different water fractions (?w = 0% to 90%), where the hydrogen bonding interaction between imine and water molecules led to suppression of photoinduced electron transfer (PET) inducing significant enhancement in fluorescence. The highly photostable nanoaggregates were explored as a selective fluorescence “turn off” sensor for phenolic nitroaromatics and the chemo-selectivity was highly pronounced for 2,4,6-trinitrophenol (picric acid), that showed efficient quenching in aqueous as well as solid phase, with a detection limit of 10 nM in aqueous medium. The quenching efficiency of the nanoaggregates can be ascribed to a combination of factors including efficient fluorescence resonance energy transfer, inner filter effect and coulombic interaction between picric acid and the aggregated probe molecules. Further, random aggregation of the pyrene derivative could be controlled for the formation of fluorescent spherical nanoparticles using Pluoronics P-123 block copolymers as encapsulating agents. The resulting composite could be used as a neoteric cell imaging probe with significantly less cytotoxicity, thus showing their potential biological applications.
关键词： aggregation induced emission,electron transfer,explosive detection,cell imaging,Fluorescent organic nanoaggregates
更新于2025-11-21 11:03:13
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Aqueous synthesis of glutathione-capped CuInS2/ZnS quantum dots-graphene oxide nanocomposite as fluorescence a??switch OFFa?? for explosive detection
摘要： This work reports a simple and fast aqueous preparation of CuInS2/ZnS-graphene oxide (CIS/ZnS-GO) nanocomposite as a fluorescence "switch OFF" probe for the fluorescence detection of 2, 4, 6-trinitrophenol (TNP.) – a raw material for various explosive devices. The as-synthesized nanocomposites was characterised using Ultraviolet–visible (UV–Vis) spectroscopy, photoluminescence (PL) spectroscopy, high resolution transmission electron microscopy (HR-TEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and Raman scattering. The PL studies revealed that the adsorption of TNP onto GO via p-p stacking enhanced the charges transfer from CuInS2/ZnS-GO to the analyte. The limit of detection (LOD) for the analyte is 57 lΜ.
关键词： Nanocomposite,Explosive,Quenching,Trinitrophenol,Fluorescence,Detection
更新于2025-11-19 16:46:39
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Peptide-Functionalized Quantum Dots for Rapid Label-Free Sensing of 2,4,6-Trinitrotoluene
摘要： Explosive compounds, such as 2,4,6-trinitrotoluene (TNT), pose a great concern in terms of both global public security and environmental protection. There are estimated to be hundreds of TNT contaminated sites all over the world, which will affect the health of humans, wildlife, and the ecosystem. Clearly, the ability to detect TNT in soils, water supplies, and wastewater is important for environmental studies but also important for security, such as in ports and boarders. However, conventional spectroscopic detection is not practical for on-site sensing because it requires sophisticated equipment and trained personnel. We report a rapid and simple chemical sensor for TNT by using TNT binding peptides which are conjugated to fluorescent CdTe/CdS quantum dots (QDs). QDs were synthesized in the aqueous phase, and the peptide was attached directly to the surface of the QDs by using thiol groups. The fluorescent emission from the QDs was quenched in response to the addition of TNT. The response could even be observed by the naked eye. The limit of detection from fluorescence spectroscopic measurement was estimated to be approximately 375 nM. In addition to the rapid response (within a few seconds), selective detection was demonstrated. We believe this label-free chemical sensor contributes to progress for the on-site explosive sensing.
关键词： quantum dots (QDs),explosive detection,2,4,6-trinitrotoluene (TNT),label-free sensing,peptide-functionalized
更新于2025-11-14 15:23:50
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Predicting detection performance on security X-ray images as a function of image quality
摘要： Developing methods to predict how image quality affects task performance is a topic of great interest in many applications. While such studies have been performed in the medical imaging community, little work has been reported in the security X-ray imaging literature. In this work, we develop models that predict the effect of image quality on the detection of improvised explosive device (IED) components by bomb technicians in images taken using portable X-ray systems. Using a newly developed NIST-LIVE X-Ray Task Performance Database, we created a set of objective algorithms that predict bomb technician detection performance based on measures of image quality. Our basic measures are traditional Image Quality Indicators (IQIs) and perceptually-relevant Natural Scene Statistics (NSS)-based measures that have been extensively used in visible light (VL) image quality prediction algorithms. We show that these measures are able to quantify the perceptual severity of degradations and can predict the performance of expert bomb technicians to identify threats. Combining NSS- and IQI-based measures yields even better task performance prediction than either of these methods independently. We also developed a new suite of statistical task prediction models that we refer to as Quality Inspectors of X-ray images (QUIX), which we believe to be the first NSS-based model for security X-ray images. We also show that QUIX can be used to reliably predict conventional IQI metric values on distorted X-ray images.
关键词： NSS,IQI prediction,IEEE/ANSI N42.55,Image Quality,Improvised explosive devices (IEDs),Task performance study,X-ray images
更新于2025-09-19 17:15:36
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On the combination of luminescent rare earth MOF and rhodamine dopant with two sensing channels for picric acid
摘要： The present paper reported a hybrid structure for the optical recognition of PA (picric acid). This dye-MOF structure, named as R6h@EuBTC, consisted of a supporting matrix based on rare earth MOF and a sensing probe based on rhodamine dye, which was con?rmed using XRD, IR, thermal and photophysical analysis. R6h@EuBTC's rhodamine absorption in visible region was enhanced by increasing PA concentrations, showing obvious color change and consequently colorimetric sensing. R6h@EuBTC's rhodamine emission component was increased by increasing PA concentrations, while its Eu emission component was slightly quenched by increasing PA concentrations, which offered self-calibrated sensing signals for ratiometric ?uorescent sensing. Linear response and good selectivity were observed for both sensing channels with LOD of 3.9 μM. R6h@EuBTC's sensing mechanism towards PA was the combination of two procedures, which were the emission turn on effect of rhodamine component triggered by PA-released protons and the emission turn off effect of Eu component caused by its electron transfer procedure to PA, respectively. R6h@EuBTC's novelty was its two sensing channels and the practicability of naked eye detection.
关键词： Ratiometric sensing,Optical sensing,Explosive detection,Naked eye detection
更新于2025-09-19 17:15:36
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Pulsed laser irradiation of a nanoparticles sensitised RDX crystal
摘要： The laser initiation of secondary explosives presents tactical, safety and environmental advantages over traditional ignition systems utilising primary explosives. In this paper, direct ignition or initiation by pulsed laser was investigated of cyclotrimethylenetrinitramine (RDX) crystals doped with gold nanoparticles (GNPs) for the first time. A nano-seconds pulsed laser was used for direct irradiation of the crystals at the GNP’s surface-plasmon-resonance wavelength of 532 nm. RDX crystals were recrystallised from a solution containing GNPs and characterised by visual microscopy for surface coating and subsurface doping. A high-speed camera was used to observe and capture the modes of interaction between the GNPs-doped RDX crystals and pulsed laser irradiation with a new classification method. Laser fluence thresholds for ignition and initiation were established. The GNPs sensitized RDX to pulsed laser irradiation at this selected wavelength is 3 orders of magnitude more sensitive than pure RDX. Direct initiation of the GNPs doped RDX crystal at laser fluence of 0.04 J/cm 2 led to the total consumption of a crystal sample, which was unreproducible with pure RDX. The results show that GNPs are effective optical sensitizers for direct initiation of RDX crystal by low-power pulsed laser.
关键词： Gold nanoparticles,Pulsed laser,Explosive,Laser ignition
更新于2025-09-19 17:13:59
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Hierarchical Laser-Patterned Silver/Graphene Oxide Hybrid SERS Sensor for Explosive Detection
摘要： We demonstrate an ultrafast laser-ablated hierarchically patterned silver nanoparticle/graphene oxide (AgNP/GO) hybrid surface-enhanced Raman scattering (SERS) substrate for highly sensitive and reproducible detection of an explosive marker 2,4-dinitrotoluene (2,4-DNT). A hierarchical laser-patterned silver sheet (Ag?S) is achieved by ultrafast laser ablation in air with pulse energies of 25, 50, and 100 μJ. Multiple laser pulses at a wavelength of 800 nm and a pulse repetition rate of 50 fs at 1 kHz are directly focused on Ag?S to produce and deposit AgNPs onto Ag?S. The surface morphology of ablated Ag?S was evaluated using atomic force microscopy, optical pro?lometry, and ?eld emission scanning electron microscopy (FESEM). A rapid increase in the ablation rate with increasing laser energy was observed. Selected area Raman mapping is performed to understand the intensity and size distribution of AgNPs on Ag?S. Further, GO was spin-coated onto the AgNPs produced by ultrafast ablation on Ag?S. The hierarchical laser-patterned AgNP/GO hybrid structure was characterized using FESEM, high-resolution transmission electron microscopy, X-ray di?raction, Fourier transform infrared spectroscopy, and Raman spectroscopy. Further, hierarchical laser-patterned AgNP/GO hybrid structures have been utilized as SERS-active substrates for the selective detection of 2,4-DNT, an explosive marker. The developed SERS-active sensor shows good stability and high sensitivity up to picomolar (pM) concentration range with a Raman intensity enhancement of ～1010 for 2,4-DNT. The realized enhancement of SERS intensity is due to the cumulative e?ect of GO coated on Ag?S as a proactive layer and AgNPs produced by ultrafast ablation.
关键词： silver nanoparticle/graphene oxide (AgNP/GO) hybrid,ultrafast laser ablation,explosive detection,surface-enhanced Raman scattering (SERS),2,4-dinitrotoluene (2,4-DNT)
更新于2025-09-19 17:13:59
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Light‐Driven ZnO Brush‐Shaped Self‐Propelled Micromachines for Nitroaromatic Explosives Decomposition
摘要： Self-propelled micromachines have recently attracted lots of attention for environmental remediation. Developing a large-scale but template-free fabrication of self-propelled rod/tubular micro/nanomotors is very crucial but still challenging. Here, a new strategy based on vertically aligned ZnO arrays is employed for the large-scale and template-free fabrication of self-propelled ZnO-based micromotors with H2O2-free light-driven propulsion ability. Brush-shaped ZnO-based micromotors with different diameters and lengths are fully studied, which present a fast response to multicycles UV light on/off switches with different interval times (2/5 s) in pure water and slow directional motion in aqueous hydrogen peroxide solution in the absence of UV light. Light-induced electrophoretic and self-diffusiophoretic effects are responsible for these two different self-motion behaviors under different conditions, respectively. In addition, the pH of the media and the presence of H2O2 show important effects on the motion behavior and microstructure of the ZnO-based micromotors. Finally, these novel ZnO-based brush-shaped micromotors are demonstrated in a proof-of-concept study on nitroaromatic explosive degradation, i.e., picric acid. This work opens a completely new avenue for the template-free fabrication of brush-shaped light-responsive micromotors on a large scale based on vertically aligned ZnO arrays.
关键词： vertically aligned arrays,light-driven,micromotors,ZnO,explosive degradation
更新于2025-09-19 17:13:59
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Evolution of Oxidizing Inorganic Metal Salts：Ultrafast Laser Initiation Materials Based on Energetic Cationic Coordination Polymers
摘要： An effective and novel design strategy for ultrafast laser initiating materials has been established on the basis of coordination chemistry for the first time in the present work. In view of the positive effect of Ag ion and perchlorate on laser sensitivity, silver perchlorate as a representative of oxidizing inorganic metal salts was used to construct energetic cationic coordination polymer (ECCPs), which solved the embarrassing situation that these salts are difficult to be directly applied in energetic materials because of unavoidable hygroscopicity and physical mixtures inhomogeneity of oxidant and reductant. With non-energetic nitrogen-rich ligand 3-amino-1H-1,2,4-triazole-5-carbohydrazide (ATCA), one new laser-sensitive Ag(I) based ECCP [Ag(ATCA)ClO4]n (1) was successfully synthesized with compact helical structure proved by X-ray single diffraction crystal data. The physicochemical property evaluation revealed that this Ag-ECCP not only completely discarded the undesirable properties of the silver perchlorate and emerged excellent tolerance to moisture and non-corrosive property to metal shells, but also were endowed with good thermal stability and excellent safety for mechanical stimulation. Moreover, theoretical calculations based on standard molar enthalpy of formation and lead plate explosive test as the actual damage experiment have proved that the compound has a superior detonation performance (up to 6800 m s-1 and 0.511 kcal g-1) than the traditional primary explosives. More importantly, the laser initiation experiment based femtosecond laser testing system and high-speed photography demonstrated that this ECCP was an energetic material with great potential for application of the safety detonator as an ultrafast photosensitive initiating materials for laser direct initiation, whose initiation delay time is as low as 73 ms using only 200 mJ initiation energy.
关键词： coordination polymer,perchlorate,laser initiation,silver,primary explosive
更新于2025-09-16 10:30:52