Ability of Various materials to Detect Explosives Vapors by Fluorescent technologies: A Comparative Study
ABSTRACT For the development of fluorescent sensors, one of the key points is choosing the sensitive material. In this article, we aim at evaluating, under strictly identical experimental conditions, the performance of three materials for the detection of dinitrotoluene (a volatile marker of trinitrotoluene) through different parameters: response time, fluorescence intensity, sensitivity, reversibility, reaction after successive exposures and long-term stability. The results are discussed according to the nature of the sensitive materials. This first study rendered it possible to select a conjugated molecule as the best sensitive material for the development of a lab-made prototype. In a second part, the selectivity of this particular sensitive material was studied and its ability to detect TNT could be demonstrated.
- SourceAvailable from: Arash Larki
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- "Various methodologies have been reported for identification or determination of TNT, including optical colorimetric sensors , fluorescent polymers  , electrochemical sensors   quartz crystal microbalance , solid phase microextraction (SPME)– HPLC , functionalized nano-particles , surface plasmon resonance  , Raman spectroscopy  and immunoassays methods   . Although these technologies have successfully been employed, their capabilities have some limitations. "
ABSTRACT: In the present study, a simple, fast and inexpensive method based on dispersive liquid-liquid microextraction (DLLME) prior to microvolume UV-vis spectrophotometry was developed for the preconcentration and determination of trinitrotoluene (TNT). The procedure is based on the color reaction of TNT in alkaline medium and extraction into CCl4 as an ion pair assisted by trioctylmethylammonium chloride, which also acts as a disperser agent. Experimental parameters affecting the DLLME method such as pH, concentration of sodium hydroxide, amount of trioctylmethylammonium chloride, type and volume of extraction solvent were investigated and optimized. Under the optimum conditions, the limit of detection (LOD) was 0.9ng/mL and the calibration curve was linear in the range of 3-200ng/mL. The relative standard deviation for 25 and 100ng/mL of TNT were 3.7% and 1.5% (n=6), respectively. The developed DLLME method was applied for the determination of TNT in different water and soil samples. Copyright © 2015. Published by Elsevier Ireland Ltd.Forensic science international 06/2015; 251. DOI:10.1016/j.forsciint.2015.03.019 · 2.14 Impact Factor
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- "Therefore, the detection of TNT in a fast, simple, sensitive , reliable, and cost-effective manner is extremely important for practical applications ranging from minefield remediation to crime scene investigations and counter-terrorism activities  . Compared with various chemical or physical methods have been developed for this purpose, fluorescence-based chemosensing attracts much attention due to its high sensitivity and simplicity              . A TNT molecule has a low-energy unoccupied * orbital, which can accept an electron from the excited state of electron donors. "
ABSTRACT: Nanofibers with distinct luminescent property were facilely fabricated by electrospinning from porphyrinated polyimide and demonstrated as a kind of novel sensory material for trace detection of TNT vapor (10 ppb). Covalently bonding of porphyrin fluorophores into the polyimide main chains reduces the aggregation-caused fluorescence self-quenching of porphyrin and improves the physicochemical stability of the polyimide nanofibers. The large surface area-to-volume ratio and hence good gas accessibility endow the porphyrinated nanofibers with much more remarkable fluorescent quenching behavior toward trace TNT vapor than its spin-coating dense film counterparter. Besides TNT, 2,4-dinitrotoluene (DNT), 2,4,6-trinitrophenol (PA) and nitrobenzene (NB) could also quench the fluorescence of the porphyrinated nanofibers, but the quenching efficiency is much lower than that of TNT. An apparent binding affinity constant of (2.37 ± 0.19) × 107 L/mol was calculated from SPR analysis, confirming that the porphyrinated nanofibers is a promising alternative for TNT detection.Sensors and Actuators B Chemical 07/2013; 184:205–211. DOI:10.1016/j.snb.2013.04.094 · 4.10 Impact Factor
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ABSTRACT: Using salicylaldehyde and 4-aminophenyl ethanone as raw material, a Schiff base derivative 4-(2-hydroxybenzylidene-amino) phenyl ethanone was synthesized by the solid phase reaction method at room temperature. The structure of the product was characterized by elemental analysis and 1 HNMR The UV spectra, fluorescence emission spectra and fluorescence quantum yield of the title Schiff base derivative were investigated. The results showed that this Schiff base displayed superior fluorescence property. The ground state configuration of the title Schiff base was optimized by density functional theory (DFT) method at the B3LYP/6-311G level. After vibrational analysis, there is no imaginary frequency, which indicates that the structure is stable. Then the ground state configuration was optimized to the excited state configuration by the method of single excited interactions CIS. Based on the optimized structure for the ground state and excited state time-dependent density functional theory (TD-DFT) calculations were carried out at the B3LYP/6-31G level to predict the absorption spectra and the fluorescence spectra. The results show that the computed spectra were comparable with the spectra from the experiments. The relationship between the molecular structure and the fluorescence property of 4-(2-hydroxybenzylideneamino) phenyl ethanone was also discussed. The results obtained may provide some theoretical guidance for the design of new fluorescence compounds.Guang pu xue yu guang pu fen xi = Guang pu 12/2013; 33(12):3259-62. DOI:10.3964/j.issn.1000-0593(2013)12-3259-04 · 0.29 Impact Factor