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1.
Chemosphere ; 307(Pt 4): 136108, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35995197

RESUMO

Explosives are powerful destructive weapons used by criminals and terrorists across the globe and their use within military installation sites poses serious environmental health problems. Existing colorimetric sensors for triacetone triperoxide (TATP) relies on detecting its hydrolysed H2O2 form. However, such detection strategy limits the practicability for on-site TATP sensing. In this work, we have developed a novel peroxidase mimic catalytic colorimetric sensor for direct recognition of TATP. Ceria (Ce)-doped Fe3O4 nanoparticles (CeFe3O4) were synthesized via the hot-injection organic synthetic route in the presence of metal precursors and organic ligands. Thereafter, the organic-capped CeFe3O4 nanoparticles were surface-functionalized with amphiphilic polymers (Amp-poly) to render the nanoparticle stable, compact and biocompatible. Thiolated γ-cyclodextrin (γ-CD) was adsorbed on the Amp-poly-CeFe3O4 nanocomposite (NC) surface to form a γ-CD-Amp-poly-CeFe3O4 NC. γ-CD served both as a receptor and as a catalytic enhancer for TATP. Hemin (H), used as a catalytic signal amplifier was adsorbed on the γ-CD-Amp-poly-CeFe3O4 NC surface to form a γ-CD-Amp-poly-CeFe3O4-H NC that served as a functional nanozyme for the enhanced catalytic colorimetric detection of TATP. Under optimum experimental reaction conditions, TATP prepared in BIS-TRIS-Trisma Ac-KAc-NAc buffer, pH 3, was selectively and ultrasensitively detected without the need for acid hydrolysis based on the catalytic oxidation of 3,3',5,5'-tetramethylbenzidine by H2O2 in the presence of the γ-CD-Amp-poly-CeFe3O4-H hybrid nanozyme. The obtained limit of detection of ∼0.05 µg/mL when compared with other published probes demonstrated superior sensitivity. The developed peroxidase mimic γ-CD-Amp-poly-CeFe3O4-H catalytic colorimetric sensor was successfully applied to detect TATP in soil, river water and tap water samples.


Assuntos
Substâncias Explosivas , Nanocompostos , gama-Ciclodextrinas , Monofosfato de Adenosina , Colorimetria , Substâncias Explosivas/análise , Hemina , Compostos Heterocíclicos com 1 Anel , Peróxido de Hidrogênio/análise , Ligantes , Fenômenos Magnéticos , Peroxidase , Peróxidos , Polímeros , Solo , Água
2.
Chemosphere ; 294: 133641, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35077733

RESUMO

When high-energy explosives such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), 2,4,6-trinitrotoluene (TNT) are discharged into the surrounding soil and water during production, testing, open dumping, military, or civil activities, they leave a toxic footprint. The US Environmental Protection Agency has labeled RDX as a potential human carcinogen that must be degraded from contaminated sites quickly. Bioremediation of RDX is an exciting prospect that has received much attention in recent years. However, a lack of understanding of RDX biodegradation and the limitations of current approaches have hampered the widespread use of biodegradation-based strategies for RDX remediation at contamination sites. Consequently, new bioremediation technologies are required to enhance performance. In this review, we explore the requirements for in-silico analysis for producing biological models of microbial remediation of RDX in soil. On the other hand, potential gene editing methods for getting the host with target gene sequences responsible for the breakdown of RDX are also reported. Microbial formulations and biosensors for detection and bioremediation are also briefly described. The biodegradation of RDX offers an alternative remediation method that is both cost-effective and ecologically acceptable. It has the potential to be used in conjunction with other cutting-edge technologies to further increase the efficiency of RDX degradation.


Assuntos
Substâncias Explosivas , Poluentes do Solo , Trinitrotolueno , Azocinas , Biodegradação Ambiental , Substâncias Explosivas/análise , Compostos Heterocíclicos com 1 Anel/análise , Compostos Heterocíclicos com 1 Anel/metabolismo , Humanos , Solo , Poluentes do Solo/análise , Triazinas/análise , Trinitrotolueno/análise
3.
Methods Mol Biol ; 2326: 315-325, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34097279

RESUMO

Hexahydro-1,3,5-trinitro-1,3,5-triazine, commonly called RDX, is an important explosive, which is widely used in military and civic activities. As it is used, RDX is widely found in many locations and caused soil and water contamination. Many studies show that RDX is toxic to many organisms, including plants, animals, and microbes. RDX causes genetic toxicity and neurotoxicity as well as potential carcinogenesis. Even it is worse that RDX can be biotransformed into other N-nitroso derivatives, such as MNX, DNX, and TNX; these derivatives can be found in both naturally in RDX-contaminated soil and also in the animal GI tracks. To study the potential effect of RDX and its N-nitroso derivatives, this chapter presents a step-by-step method for detect RDX and its N-nitroso derivatives in animal stomach and GI tracts followed RDX exposure by gas chromatography with electron capture detector (GC/ECD). This method can also be used to detect RDX and its N-nitroso derivatives in other tissues and in other animals and plants.


Assuntos
Substâncias Explosivas/análise , Trato Gastrointestinal/metabolismo , Compostos Nitrosos/análise , Triazinas/análise , Ração Animal/análise , Animais , Substâncias Explosivas/metabolismo , Feminino , Camundongos , Compostos Nitrosos/metabolismo , Triazinas/metabolismo
4.
Chem Asian J ; 15(24): 4291-4296, 2020 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-33137228

RESUMO

Widespread use of picric acid (PA) in chemical industries and deadly explosives poses dreadful impact on all living creatures as well as the natural environment and has raised global concerns that necessitate the development of fast and efficient sensing platforms. To address this issue, herein, we report a perylenediimide-peptide conjugate, PDI-1, for detection of PA in methanol. The probe displays typical aggregation caused quenching (ACQ) behaviour and exhibits a fluorescence "turn-off" sensory response towards PA which is unaffected by the presence of other interfering nitroaromatic compounds. The sensing mechanism involves PA induced aggregation of the probe into higher order tape like structures which leads to quenching of emission. The probe possesses a low detection limit of 5.6 nM or 1.28 ppb and a significantly high Stern-Volmer constant of 6.87×104  M-1 . It also exhibits conducting properties in the presence of PA vapours and thus represents a prospective candidate for vapour phase detection of PA. This is, to the best of our knowledge, the first example of a perylenediimide based probe that demonstrates extremely specific, selective and sensitive detection of PA and thus grasps the potential for application in practical scenarios.


Assuntos
Corantes Fluorescentes/química , Imidas/química , Perileno/análogos & derivados , Picratos/análise , Espectrometria de Fluorescência/métodos , Substâncias Explosivas/análise , Gases/química , Limite de Detecção , Peptídeos/química , Perileno/química
5.
J Chromatogr A ; 1624: 461193, 2020 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-32540060

RESUMO

Polyimide (PI) microspheres assembled by nanosheets were used for bar adsorptive microextraction (BAµE) for the first time. The PI microsphere possessed self-organized hierarchical nanostructure, large specific surface area (170 m2/g) and good thermostability (up to 400 °C). The BAµE device was prepared by adhering the PI microspheres on a quartz bar with Kapton double sided tape. Trace nitroaromatic explosives in environmental waters were extracted by the BAµE device, desorbed by thermal desorption (TD), and analyzed by gas chromatography-mass spectrometry (GC-MS). The reproducibility of five BAµE devices prepared in parallel was less than 13.0% (expressed as relative standard deviation, RSD). The BAµE device could stand up to 30 extraction/desorption cycles without decrease of extraction efficiency. The results of method validation showed that the BAµE-TD/GC-MS method possessed wide linearity (0.05-50 µg/L or 0.05-20 µg/L), high correlation coefficients (> 0.9987), good precision (RSDs < 11.8%), low detection limits (0.005-0.013 µg/L) and high enrichment factors (528-1410). Relative recoveries were in the range of 72.2-122.6% with RSDs between 0.1% and 10.5% for real water samples. These results proved that the proposed method was a good choice for determination of organic pollutants in water samples.


Assuntos
Substâncias Explosivas/análise , Imidas/química , Nanoestruturas/química , Microextração em Fase Sólida/métodos , Poluentes Químicos da Água/análise , Adsorção , Substâncias Explosivas/isolamento & purificação , Cromatografia Gasosa-Espectrometria de Massas , Limite de Detecção , Microesferas , Reprodutibilidade dos Testes , Microextração em Fase Sólida/instrumentação , Poluentes Químicos da Água/isolamento & purificação
6.
Arch Toxicol ; 94(6): 1941-1953, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32303806

RESUMO

The seas worldwide are threatened by a "new" source of pollution: millions of tons of all kind of warfare material have been dumped intentionally after World War I and II, in addition to mine barriers, failed detonations as well as shot down military planes and sunken ship wrecks carrying munitions. For example, in the German parts of the North and Baltic Sea approximately 1.6 million metric tons of toxic conventional explosives (TNT and others) and more than 5000 metric tons of chemical weapons are present. Such unexploded ordnance (UXO) constitutes a direct risk of detonation with increased human access (fisheries, water sports, cable constructions, wind farms and pipelines). Moreover, after more than 70 years of resting on the seabed, the metal shells of these munitions items corrode, such that chemicals leak out and distribute in the marine environment. Explosive chemicals such as TNT and its derivatives are known for their toxicity and carcinogenicity. In order not to endanger today's shipping traffic or the installation of pipelines and offshore plants by uncontrolled explosions, controlled blast-in-place (BiP) operations of these dangerous relics is a common practice worldwide. However, blast-in-place methods of in situ munitions disposal often result in incomplete (low-order) detonation, leaving substantial quantities of the explosive material in the environment. In the present free field investigation, we placed mussels (Mytilus spp.) as a biomonitoring system in an area of the Baltic Sea where BiP operations took place and where, by visual inspections by scientific divers, smaller and larger pieces of munitions-related materials were scattered on the seafloor. After recovery, the mussels were transferred to our laboratory and analyzed for TNT and its derivatives via gas chromatography and mass spectroscopy. Our data unequivocally demonstrate that low-order BiP operations of dumped munitions in the sea lead to multiple increases in the concentration of TNT and its metabolites in the mussels when compared to similar studies at corroding but still encased mines. For this reason, we explicitly criticize BiP operations because of the resulting environmental hazards, which can ultimately even endanger human seafood consumers.


Assuntos
Explosões , Substâncias Explosivas/análise , Contaminação de Alimentos/análise , Mytilus edulis/química , Alimentos Marinhos/análise , Gerenciamento de Resíduos , Resíduos/análise , Poluentes Químicos da Água/análise , II Guerra Mundial , I Guerra Mundial , Animais , Monitoramento Biológico , Qualidade de Produtos para o Consumidor , Substâncias Explosivas/efeitos adversos , Humanos , Oceanos e Mares , Medição de Risco , Alimentos Marinhos/efeitos adversos , Resíduos/efeitos adversos , Poluentes Químicos da Água/efeitos adversos
7.
Biosens Bioelectron ; 153: 112030, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31989939

RESUMO

A novel peptide-based three-dimensional probe called "peptide matrix," inspired by the antibody paratope region, was fabricated on a surface plasmon resonance (SPR) sensor chip to enhance the sensitivity of detecting the explosive 2,4,6-trinitrotoluene (TNT). Although peptide aptamer is an attractive candidate for a molecular recognition probe because of its ease of synthesis and chemical stability, it still has difficulty in applying to highly sensitive (i.e. parts-per-billion (ppb) or sub-ppb level) detections. Thus, we developed the concept of peptide matrix structure, which is constructed by consecutive disulfide bond formation between a large number of peptide fragments. This robust three-dimensional structure displays multiple binding sites which can efficiently associate with each TNT molecule. The peptide matrix lowered the dissociation constant (KD) by two orders of magnitude compared to the linear peptide aptamer, estimating KD as 10.1 nM, which is the lowest concentration reported by using peptide-based TNT probe. Furthermore, the concentration limit of detection of peptide matrix modified SPR sensor was 0.62 ppb, and hence comparable to single-chain variable fragment (scFv)-based TNT sensors. To our knowledge, this is the first report demonstrating peptide matrix fabrication and its application for small explosive molecule detection. This peptide matrix-based approach, which has the advantage of simple synthesis and high sensitivity, will be applicable to many other small-molecule label-free detections.


Assuntos
Anticorpos Monoclonais/química , Aptâmeros de Peptídeos/química , Substâncias Explosivas/análise , Peptídeos/química , Ressonância de Plasmônio de Superfície/métodos , Trinitrotolueno/análise , Transportadores de Cassetes de Ligação de ATP , Sequência de Aminoácidos , Ligação Competitiva , Cisteína/química , Dissulfetos/química , Desenho de Equipamento , Limite de Detecção , Estrutura Molecular , Técnicas de Síntese em Fase Sólida , Propriedades de Superfície , Termodinâmica
8.
Molecules ; 24(23)2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31816831

RESUMO

The dynamic sorption concentration of explosive vapours on concentrators made of a metal mesh, and the transportation of explosive vapours through the extended metal channels are considered. The efficiency of the concentration and transportation is determined by the breakthrough of the substance's molecules through the channels. The research methods we used were breakthrough calculation theory and experiment. When calculating the breakthrough, a mesh was presented as a set of parallel identical channels. Wire mesh and extended channels were made of stainless steel. The breakthrough is determined through the specific frequency of the collisions between the molecules and the channel's surface. This is presented as a function of the ratio of the substance diffusion flow to the channel's surface to the airflow through the channel. The conditions for high-speed concentration, complete capture of explosive vapours, and low vapour losses during their transportation through the extended channels were determined theoretically and experimentally. For a concentrator made of a mesh, the condition of a high concentration rate at a high breakthrough (up to 80%) was determined. The described sorption concentration is used in portable gas chromatographic detectors of explosive vapours of the EKHO series.


Assuntos
Cromatografia Gasosa/instrumentação , Substâncias Explosivas/análise , Monitoramento Ambiental/instrumentação , Gases , Cinética
9.
Spectrochim Acta A Mol Biomol Spectrosc ; 219: 129-134, 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31030040

RESUMO

Since the introduction of a benchtop vacuum ultraviolet (VUV) absorption spectroscope with an increased wavelength range towards to the high energetic ultraviolet radiation, gas chromatography coupled to VUV has been proven a powerful tool in several fields of application such as petroleomics, permanent gas analytic, pesticide analytic and many more. In this study, the potential of GC-VUV for investigations was examined, focusing on drug- and explosive precursors as well as chemical warfare simulants. The ability of VUV absorption spectra to differentiate isomers is presented, among others for nitroaromatics. In addition, the limit of detection for target compounds was determined to 0.7 ng absolute on column. Furthermore, non-negative matrix factorization (NMF) was successfully implemented as alternative deconvolution approach and evaluated for the deconvolution of unknown substances. In comparison, the spectral library-based deconvolution was applied to a standard mixture and a simulated case study. The results reveal that the NMF is a useful additional tool for deconvolution because, unlike library-based deconvolution, it allows to investigate unknown substances as well.


Assuntos
Substâncias para a Guerra Química/análise , Cromatografia Gasosa/métodos , Substâncias Explosivas/análise , Preparações Farmacêuticas/análise , Espectrofotometria Ultravioleta/métodos , Isomerismo , Vácuo
10.
Biosens Bioelectron ; 129: 284-291, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30245166

RESUMO

Silica nanopores have electron channels and ion channels interpenetrating each other, which prompt the use of this structure for creating efficient electronic devices. In this study, silica nanopores membrane modified screen printed electrodes were applied in a smartphone-based electrochemiluminescence system for nitroaromatic explosives detection. Universal serial bus-on the go (USB-OTG) and camera on smartphone were used as the electrical stimulation and luminescence capture, respectively. ⎕Multimode methods including (red-green-blue) RGB, (hue-saturation-brightness) HSB, and Gray were proposed for luminescence analysis. Specific polypeptides were immobilized on the nanopores modified electrodes for nitroaromatic explosives sensing. With positive-charged tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)32+) as electrochemiluminescence label, the increase in luminescence was associated with the selective ion channels and the well-conductive electron channels in the negative-charged nanopores. Besides, on account of the large specific surface area, nanopores modified screen printed electrodes showed stable and uniform luminescence. Results showed that the nanopores-enhanced electrochemiluminescence on smartphone covered a linear dynamic range from 10-7 mg/mL to 10-3 mg/mL for nitroaromatic explosives detection with the detection limit of 2.3 × 10-9 mg/mL. Therefore, high-efficient photo-electricity conversion capabilities of nanopores made it a kind of promising platform for sensitive and stable electrochemiluminescence. Furthermore, smartphone-based electrochemiluminescence with disposable screen printed electrodes could facilitate the mobile monitoring of biochemical analytes in the fields of environment, security, and health.


Assuntos
Técnicas Biossensoriais/instrumentação , Dinitrobenzenos/análise , Substâncias Explosivas/análise , Nanoporos/ultraestrutura , Dióxido de Silício/química , Tolueno/análogos & derivados , Trinitrotolueno/análise , Técnicas Eletroquímicas/instrumentação , Eletrodos , Desenho de Equipamento , Limite de Detecção , Medições Luminescentes/instrumentação , Peptídeos/química , Smartphone , Tolueno/análise
11.
Anal Biochem ; 550: 49-53, 2018 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-29655769

RESUMO

A near infrared (NIR) optical biosensor based on peptide functionalized single-walled carbon nanotubes (SWCNTs) hybrids for 2,4,6-trinitrotoluene (TNT) explosive detection was developed. The TNT binding peptide was directly anchored on the sidewall of the SWCNTs using the π-π interaction between the aromatic amino acids and SWCNTs, forming the peptide-SWCNTs hybrids for near infrared absorption spectra measurement. The evidence of the morphology of peptide-SWCNTs hybrids was obtained using atomic force microscopy (AFM). The results demonstrated that peptide-SWCNTs hybrids based NIR optical biosensor exhibited sensitive and highly selective for TNT explosive determination, addressing a promising optical biosensor for security application.


Assuntos
Técnicas Biossensoriais/métodos , Substâncias Explosivas/análise , Nanotubos de Carbono/química , Peptídeos/química , Trinitrotolueno/análise , Espectrofotometria Infravermelho/métodos
12.
J Sep Sci ; 41(3): 639-647, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29086477

RESUMO

A new method for quantification of 12 nitroaromatic compounds including 2,4,6-trinitrotoluene, its metabolites and 2,4,6-trinitrophenyl-N-methylnitramine with microextraction by packed sorbent followed by gas chromatography and mass spectrometric detection in environmental and biological samples is developed. The microextraction device employs 4 mg of C18 silica sorbent inserted into a microvolume syringe for sample preparation. Several parameters capable of influencing the microextraction procedure, namely, number of extraction cycles, washing solvent, volume of washing solvent, elution solvent, volume of eluting solvent and pH of matrix, were optimized. The developed method produced satisfactory results with excellent values of coefficient of determination (R2  > 0.9804) within the established calibration range. The extraction yields were satisfactory for all analytes (> 89.32%) for aqueous samples and (> 87.45%) for fluidic biological samples. The limits of detection values lie in the range 14-828 pg/mL.


Assuntos
Substâncias Explosivas/análise , Cromatografia Gasosa-Espectrometria de Massas , Limite de Detecção , Microextração em Fase Sólida/métodos , Trinitrotolueno/análise , Adsorção , Líquidos Corporais , Calibragem , Carbono/química , Substâncias Explosivas/sangue , Substâncias Explosivas/urina , Gases , Voluntários Saudáveis , Humanos , Concentração de Íons de Hidrogênio , Reprodutibilidade dos Testes , Rios , Solventes , Trinitrotolueno/sangue , Trinitrotolueno/urina , Água
13.
Environ Sci Process Impacts ; 19(5): 711-719, 2017 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-28394378

RESUMO

A novel biochar-coated zero-valent iron [Fe(0)], which was synthesized with rice straw and Fe(0), was applied to remove nitro explosives (2,4,6-trinitrotoluene and hexahydro-1,3,5-trinitro-1,3,5-triazine) and halogenated phenols (2,4-dibromophenol and 2,4-difluorophenol) from contaminated waters. Due to the presence of biochar on the outside, the removal of nitro explosives and halogenated phenols was significantly enhanced via sorption. The sorbed contaminants were further transformed into reductive products, indicating that the inner Fe(0) played the role of a reductant in the biochar-coated Fe(0). Compared to direct reduction with Fe(0), the reductive transformation with biochar-coated Fe(0) was markedly enhanced, suggesting that the biochar in biochar-coated Fe(0) may act as an electron transfer mediator. Further experiments showed that the surface functional groups of biochar were involved in the catalytic enhancement of electron transfer. Our results suggested that biomass could be used to synthesize a novel sorbent and catalyst for treating redox-sensitive contaminants in natural and engineered systems.


Assuntos
Carvão Vegetal/química , Substâncias Explosivas/análise , Ferro/química , Fenóis/análise , Triazinas/análise , Trinitrotolueno/análise , Poluentes Químicos da Água/análise , Adsorção , Biomassa , Catálise , Halogenação , Oxirredução , Fenóis/química , Poluentes Químicos da Água/química , Purificação da Água/métodos
14.
Nat Mater ; 16(2): 264-272, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27798623

RESUMO

Plant nanobionics aims to embed non-native functions to plants by interfacing them with specifically designed nanoparticles. Here, we demonstrate that living spinach plants (Spinacia oleracea) can be engineered to serve as self-powered pre-concentrators and autosamplers of analytes in ambient groundwater and as infrared communication platforms that can send information to a smartphone. The plants employ a pair of near-infrared fluorescent nanosensors-single-walled carbon nanotubes (SWCNTs) conjugated to the peptide Bombolitin II to recognize nitroaromatics via infrared fluorescent emission, and polyvinyl-alcohol functionalized SWCNTs that act as an invariant reference signal-embedded within the plant leaf mesophyll. As contaminant nitroaromatics are transported up the roots and stem into leaf tissues, they accumulate in the mesophyll, resulting in relative changes in emission intensity. The real-time monitoring of embedded SWCNT sensors also allows residence times in the roots, stems and leaves to be estimated, calculated to be 8.3 min (combined residence times of root and stem) and 1.9 min mm-1 leaf, respectively. These results demonstrate the ability of living, wild-type plants to function as chemical monitors of groundwater and communication devices to external electronics at standoff distances.


Assuntos
Engenharia Genética/métodos , Hidrocarbonetos Aromáticos/metabolismo , Compostos de Nitrogênio/metabolismo , Peptídeos/metabolismo , Plantas Geneticamente Modificadas/fisiologia , Spinacia oleracea/fisiologia , Biônica/métodos , Substâncias Explosivas/análise , Hidrocarbonetos Aromáticos/análise , Raios Infravermelhos , Nanotubos de Carbono/química , Compostos de Nitrogênio/análise , Peptídeos/genética
15.
J Chromatogr A ; 1459: 145-151, 2016 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-27397925

RESUMO

We present a novel method for coupling thin layer chromatography (TLC) with ion mobility spectrometry (IMS) using laser desorption technique (LD). After separation of the compounds by TLC, the TLC surface was sampled by the LD-IMS without any further manipulation or preparation. The position of the laser was fixed and the TLC plate was moved in desired directions by the motorized micro-positioning stage. The method was successfully applied to analyze the TLC plates containing explosives (tri nitro toluene, 1,3,5-trinitro- 1,3,5-triazacyclohexane, pentaerythritol tetranitrate, 2,4-dinitro toluene and 3,4-dinitro toluene), amino acids (alanine, proline and isoleucine), nicotine and diphenylamine mixtures and detection limits for these compounds were determined. Combination of TLC with LD-IMS technique offers additional separation dimension, allowing separation of overlapping TLC analytes. The time for TLC sampling by LD-IMS was less than 80s. The scan rate for LD is adjustable so that fast and effective analysis of the mixtures is possible with the proposed method.


Assuntos
Cromatografia em Camada Fina , Substâncias Explosivas/análise , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Aminoácidos/análise , Difenilamina/química , Limite de Detecção , Nicotina/análise
16.
Appl Radiat Isot ; 117: 27-31, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27102306

RESUMO

Regardless the motivation terrorism is the most important risk for the national security in many countries. Attacks with explosives are the most common method used by terrorists. Therefore several procedures to detect explosives are utilized; among these methods are the use of neutrons and photons. In this study the Monte Carlo method an explosive detection system using a 241AmBe neutron source was designed. In the design light water, paraffin, polyethylene, and graphite were used as moderators. In the work the explosive RDX was used and the induced gamma rays due to neutron capture in the explosive was estimated using NaI(Tl) and HPGe detectors. When light water is used as moderator and HPGe as the detector the system has the best performance allowing distinguishing between the explosive and urea. For the final design the Ambient dose equivalent for neutrons and photons were estimated along the radial and axial axis.


Assuntos
Amerício/análise , Substâncias Explosivas/análise , Substâncias Explosivas/química , Método de Monte Carlo , Terapia por Captura de Nêutron/instrumentação , Espectrometria gama/instrumentação , Amerício/química , Simulação por Computador , Desenho Assistido por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Modelos Estatísticos , Terapia por Captura de Nêutron/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espectrometria gama/métodos
17.
Appl Spectrosc ; 70(5): 888-96, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-27006020

RESUMO

Portable gas chromatography-mass spectrometry (GC-MS) systems are being deployed for field use, and are designed with this goal in mind. Performance characteristics of instruments that are successful in the field are different from those of equivalent technologies that are successful in a laboratory setting. These field-portable systems are extending the capabilities of the field user, providing investigative leads and confirmatory identifications in real time. Many different types of users benefit from the availability of this technology including emergency responders, the military, and law-enforcement organizations. This manuscript describes performance characteristics that are important for field-portable instruments, especially field-portable GC-MS systems, and demonstrates the value of this equipment to the disciplines of explosives investigations, fire investigations, and counterfeit-drug detection. This paper describes the current state of portable GC-MS technology, including a review of the development of portable GC-MS, as well as a demonstration of the value of this capability using different examples.


Assuntos
Substâncias Explosivas/análise , Cromatografia Gasosa-Espectrometria de Massas/instrumentação , Preparações Farmacêuticas/análise , Contaminação de Medicamentos , Socorristas , Humanos , Militares , Miniaturização/instrumentação
18.
J Mass Spectrom ; 51(2): 132-40, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26889929

RESUMO

In this work, a low-pressure air dielectric-barrier discharge (DBD) ion source using a capillary with the inner diameter of 0.115 and 12 mm long applicable to miniaturized mass spectrometers was developed. The analytes, trinitrotoluene (TNT), 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), 1,3,5,7-tetranitroperhydro-1,3,5,7-tetrazocine (HMX), pentaerythritol tetranitrate (PETN), nitroglycerine (NG), hexamethylene triperoxide diamine (HMTD), caffeine, cocaine and morphine, introduced through the capillary, were ionized by a low-pressure air DBD. The ion source pressures were changed by using various sizes of the ion sampling orifice. The signal intensities of those analytes showed marked pressure dependence. TNT was detected with higher sensitivity at lower pressure but vice versa for other analytes. For all analytes, a marked signal enhancement was observed when a grounded cylindrical mesh electrode was installed in the DBD ion source. Among nine analytes, RDX, HMX, NG and PETN could be detected as cluster ions [analyte + NO3 ](-) even at low pressure and high temperature up to 180 °C. The detection indicates that these cluster ions are stable enough to survive under present experimental conditions. The unexpectedly high stabilities of these cluster ions were verified by density functional theory calculation.


Assuntos
Substâncias Explosivas/análise , Gases/química , Espectrometria de Massas/métodos , Preparações Farmacêuticas/análise , Pressão Atmosférica , Modelos Moleculares
19.
Talanta ; 144: 439-44, 2015 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-26452845

RESUMO

The development of explosives detection technologies has increased significantly over the years as environmental and national security agencies implement tighter pollution control measures and methods for improving homeland security. 2, 4, 6-Trinitrotoluene (TNT), known primarily as a component in munitions, has been targeted for both its toxicity and carcinogenic properties that if present at high concentrations can be a detriment to both humans, marine and plant ecosystems. Enabling end users with environmental detection and monitoring systems capable of providing real-time, qualitative and quantitative chemical analysis of these toxic compounds would be extremely beneficial. Reported herein is the development of a multi-channeled microfluidic device immobilized with single chain fragment variable (scFv) recombinant proteins specific for the explosive, TNT. Fluorescence displacement immunoassays performed under constant flow demonstrated trace level sensitivity and specificity for TNT. The utility of three multi-channeled devices immobilized with either (1) scFv recombinant protein, (2) biotinylated-scFv (bt-scFv) and (3) monoclonal anti-TNT (whole IgG molecule) were investigated and compared. Fluorescence dose response curves, crossreactivity measurements and limits of detection (LOD) for TNT were determined. Fluorescence displacement immunoassays for TNT in natural seawater demonstrated detection limits at sub-parts-per-billion levels (0.5 ppb) utilizing the microfluidic device with immobilized bt-scFv.


Assuntos
Anticorpos Imobilizados/imunologia , Substâncias Explosivas/análise , Dispositivos Lab-On-A-Chip , Anticorpos de Cadeia Única/imunologia , Trinitrotolueno/análise , Poluentes Químicos da Água/análise , Anticorpos Imobilizados/química , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Avidina/química , Biotinilação , Substâncias Explosivas/imunologia , Fluorescência , Imunoglobulina G/química , Imunoglobulina G/imunologia , Limite de Detecção , Proteínas Recombinantes/química , Proteínas Recombinantes/imunologia , Água do Mar/química , Anticorpos de Cadeia Única/química , Trinitrotolueno/imunologia , Poluentes Químicos da Água/imunologia
20.
Anal Chem ; 87(8): 4436-41, 2015 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-25815534

RESUMO

The rapid and sensitive detection of nitroaromatic compounds is of great significance for human health, the environment, and public security. The present work reports on the extraction and electrochemical analysis of trace nitroaromatic compounds, such as explosives and organophosphate pesticides (OPs), using the indium tin oxide (ITO) electrodes modified with a highly ordered and aligned binary assembly of silica mesochannels and micelles (BASMM). With a pore diameter of ca. 2-3 nm, silica mesochannels (SMs) perpendicularly oriented to the ITO electrode surface can provide hard and robust supports to confine the soft cylindrical micelles formed by the aggregation of cationic surfactants, namely, cetyltrimethylammonium bromide (CTAB). Due to the organized self-assembly of hydrocarbon tails of CTAB surfactants, each micelle has a hydrophobic core, which acts as an excellent adsorbent for rapid extraction and preconcentration of trace nitroaromatic compounds from aqueous solutions via the hydrophobic effect. Furthermore, the cylindrical micelles are directly in contact with the underlying electrode surface, to which extracted compounds can freely diffuse and then be reduced therein, thus allowing their determination by means of voltammetry. Using the BASMM/ITO sensor, electrochemical analysis of trace nitroaromatic explosives, including 2,4,6-trinitrotoluene (TNT), 2,4,6-trinitrophenol, 2,6-dinitrotoluene, 3-nitrophenol, and nitrobenzene, and OPs, such as paraoxon, methyl parathion, and fenitrothion, was achieved with a fast response, wide linear range, high sensitivity, and low detection limit at the ppb level. TNT and paraoxon in real apple, tea, and water samples were also determined. By combining the heterogeneous extraction and determination in one ordered binary nanostructure, the BASMM sensor provides a very simple, rapid, and cost-effective way for analysis of nitroaromatic compounds and can be extended to a wide range of lipophilic yet redox-active analytes.


Assuntos
Compostos de Cetrimônio/química , Técnicas Eletroquímicas , Substâncias Explosivas/análise , Nitrocompostos/análise , Praguicidas/análise , Dióxido de Silício/química , Tensoativos/química , Cetrimônio , Micelas
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