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1.
J Chromatogr A ; 1629: 461506, 2020 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-32866822

RESUMO

The development of a new, lower cost method for trace explosives recovery from complex samples is presented using miniaturised, click-together and leak-free 3D-printed solid phase extraction (SPE) blocks. For the first time, a large selection of ten commercially available 3D printing materials were comprehensively evaluated for practical, flexible and multiplexed SPE using stereolithography (SLA), PolyJet and fused deposition modelling (FDM) technologies. Miniaturised single-piece, connectable and leak-free block housings inspired by Lego® were 3D-printed in a methacrylate-based resin, which was found to be most stable under different aqueous/organic solvent and pH conditions, using a cost-effective benchtop SLA printer. Using a tapered SPE bed format, frit-free packing of multiple different commercially available sorbent particles was also possible. Coupled SPE blocks were then shown to offer efficient analyte enrichment and a potentially new approach to improve the stability of recovered analytes in the field when stored on the sorbent, rather than in wet swabs. Performance was measured using liquid chromatography-high resolution mass spectrometry and was better, or similar, to commercially available coupled SPE cartridges, with respect to recovery, precision, matrix effects, linearity and range, for a selection of 13 peroxides, nitramines, nitrate esters and nitroaromatics. Mean % recoveries from dried blood, oil residue and soil matrices were 79 ± 24%, 71 ± 16% and 76 ± 24%, respectively. Excellent detection limits between 60 fg for 3,5-dinitroaniline to 154 pg for nitroglycerin were also achieved across all matrices. To our knowledge, this represents the first application of 3D printing to SPE of so many organic compounds in complex samples. Its introduction into this forensic method offered a low-cost, 'on-demand' solution for selective extraction of explosives, enhanced flexibility for multiplexing/design alteration and potential application at-scene.


Assuntos
Substâncias Explosivas/análise , Extração em Fase Sólida/métodos , Cromatografia Líquida de Alta Pressão , Substâncias Explosivas/isolamento & purificação , Concentração de Íons de Hidrogênio , Limite de Detecção , Espectrometria de Massas , Metacrilatos/química , Nitroglicerina/análise , Nitroglicerina/isolamento & purificação , Peróxidos/análise , Peróxidos/isolamento & purificação , Impressão Tridimensional , Solventes/química
2.
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
3.
Chemosphere ; 250: 126210, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32109698

RESUMO

This study utilized innovative analyses to develop multiple lines of evidence for natural attenuation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in groundwater at the U.S. Department of Energy's Pantex Plant. RDX, as well as the degradation product 4-nitro-2,4-diazabutanal (NDAB; produced by aerobic biodegradation or alkaline hydrolysis) were detected in a large portion of the plume, with lower concentrations of the nitroso-containing metabolites produced during anaerobic biodegradation. 16S metagenomic sequencing detected the presence of bacteria known to aerobically degrade RDX (e.g., Gordonia, Rhodococcus) and NDAB (Methylobacterium), as well as the known anoxic RDX degrader Pseudomonas fluorescens I-C. Proteomic analysis detected both the aerobic RDX degradative enzyme XplA, and the anoxic RDX degradative enzyme XenB. Groundwater enrichment cultures supplied with low concentrations of labile carbon confirmed the potential of the extant groundwater community to aerobically degrade RDX and produce NDAB. Compound-specific isotope analysis (CSIA) of RDX collected at the site showed fractionation of nitrogen isotopes with δ15N values ranging from approximately -5‰ to +9‰, providing additional evidence of RDX degradation. Taken together, these results provide evidence of in situ RDX degradation in the Pantex Plant groundwater. Furthermore, they demonstrate the benefit of multiple lines of evidence in supporting natural attenuation assessments, especially with the application of innovative isotopic and -omic technologies.


Assuntos
Biodegradação Ambiental , Água Subterrânea/química , Triazinas/metabolismo , Poluentes Químicos da Água/metabolismo , Substâncias Explosivas/análise , Gordonia (Bactéria)/metabolismo , Água Subterrânea/microbiologia , Isótopos de Nitrogênio/análise , Proteômica , Rhodococcus/metabolismo , Triazinas/análise , Poluentes Químicos da Água/análise
4.
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
5.
J Chromatogr A ; 1611: 460580, 2020 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-31601423

RESUMO

The feasibility of measuring the aging and degradation of PBX 9501 via online two dimensional liquid chromatography (LC × LC) is investigated, and a preliminary instrumental setup and method is developed. Plastic-Bonded eXplosive (PBX) 9501 is nominally composed of 94.9 wt% HMX, 2.5 wt% Estane® 5703 (poly (ester urethane)), 2.5 wt% BDNPA/F (nitroplasticizer), 0.1 wt% Irganox 1010 and PBNA (N-phenyl-naphthylamine) at low concentrations. When exposed to various environmental conditions, PBX 9501 will degrade through different pathways. Because PBX 9501 is composed of both low molecular weight compounds (BDNPA/F, Irganox 1010, PBNA, and potential degradation products) and high molecular weight compounds (Estane® 5703), analysis is normally performed via two independent analyses. The low molecular weight species are analyzed via high pressure liquid chromatography (HPLC) and the high molecular weight species via size exclusion chromatography (SEC). While these individual techniques yield information about the aging of PBX 9501, the combination of HPLC and SEC (i.e. HPLC × SEC) can simplify and streamline the analyses while also providing additional chemical information. A simplified sample preparation method is proposed for LC × LC analysis. Various SEC columns and HPLC column selection, flow rate, and gradient ramps were investigated for their application of measuring aged PBX 9501. Finally, two LC × LC separations of a library standard of PBX 9501 and a sample of aged PBX 9501 are compared.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Substâncias Explosivas/análise , Plásticos/análise , Cromatografia em Gel , Uretana/análise
6.
Molecules ; 24(23)2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31783515

RESUMO

Explosives detection systems (EDS) based on X-ray are used at airports to screen baggage for the presence of explosives. In Europe and the United States, EDS equipment is tested extensively by specialist test centres prior to approval for operational use in airports. Once EDS are installed in airports, however, it can be challenging to test the EDS equipment and verify that it continues to perform at the highest level, because of the impracticality of introducing bulk explosives into civil aviation airports. We have developed inert, non-toxic polymer-bonded simulants and validated them against real explosives using EDS equipment. The accuracy of our simulants is within 1% of the target bulk density, and within 2% of the target effective atomic number, and the materials have a stability of at least 4 years, with an uncertainty of 0.5%. The simulants generate alarms in almost 100% of cases on a wide range of commercial EDS models, and we consider the simulants fit for purpose for use during testing of EDS equipment at airports.


Assuntos
Substâncias Explosivas/análise , Polímeros/química , Raios X , Aeroportos , Aviação , Europa (Continente) , Substâncias Explosivas/química , Ciência dos Materiais , Polímeros/análise , Poliuretanos/química , Radiografia , Padrões de Referência , Software , Fatores de Tempo , Incerteza , Estados Unidos
7.
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
8.
Environ Res ; 177: 108621, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31421450

RESUMO

2,4,6-trinitrophenol (TNP) is environmentally deleterious substance that has been of pressing societal concern. Therefore, developing a convenient and reliable platforms for its fast and efficient detection is of paramount importance from security point of view. Herein, amphiphilic fluorescent carbon dots (CDs) were prepared by a simple solvothermal method. CDs exhibit high selectivity and sensitivity on TNP in the polar and apolar solvent and even natural water samples. Moreover, the simple and portable indicator paper can be prepared conveniently and used for sensing TNP visually with high sensitivity and fast response. Research findings obtained from this study would assist in the development of portable devices for the on-site and real-time detection of environmental hazards.


Assuntos
Carbono , Poluentes Ambientais/análise , Substâncias Explosivas/análise , Picratos/análise , Pontos Quânticos , Monitoramento Ambiental , Corantes Fluorescentes
9.
Environ Toxicol Chem ; 38(11): 2383-2391, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31365142

RESUMO

Munitions constituents (MC) may be released into aquatic environments as a result of underwater military munitions (UWMM) corrosion and breach. The present study investigated the release of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) from Composition B fragments under 2 realistic exposure scenarios in a large flume with flow set at 15 cm/s: the first represented the release of MC from fully exposed Composition B, and the second represented release through a small hole, simulating a breached munition. Release of MC through a small hole was approximately 10 times lower than from exposed Composition B, demonstrating the strong influence of exposure to flow on release. The rate of release of MC into the flume was similar to that previously reported in a related field experiment, but a similar mass loss resulted in MC concentration in the field >300 times lower, likely by the dilution effect of hydrodynamic transport. The present study corroborates previous findings of release of MC at UWMM sites resulting in concentrations below the toxicity threshold to most species. In the flume water, MC was quantified using frequent grab sampling and polar organic chemical integrative samplers (POCIS). For TNT, POCIS-estimated time-weighted average concentrations were up to 40% higher than those derived from grab samples, whereas for RDX differences were 6% or less, demonstrating that POCIS provide reliable temporal integration of changing environmental concentrations for common MC. Environ Toxicol Chem 2019;38:2383-2391. Published 2019 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.


Assuntos
Monitoramento Ambiental/métodos , Substâncias Explosivas/análise , Compostos Orgânicos/análise , Poluentes Químicos da Água/análise , Água/química , Análise de Regressão , Fatores de Tempo , Triazinas/análise , Trinitrotolueno/análise
10.
Talanta ; 204: 189-197, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31357281

RESUMO

It is fairly crucial to detect inorganic explosives through a sensitive and fast method in the field of public safety, nevertheless, the high non-volatility and stability characteristics severely confine their accurate on-site detection from a real-world surface. In this work, an efficient, simple and cost effective method was developed to fabricate uniform silver nanoparticles (AgNPs) immobilized on polyurethane (PU) sponge through the in-situ reduction of polydopamine (PDA) based on mussel-inspired surface chemistry, in virtue of a large quantities catechol and amine functional groups. The formed PU@PDA@Ag sponges exhibited high SERS sensitivity, uniformity and reproducibility to 4-Aminothiophenol (4-ATP) probe molecule, and the limit of detection was calculated to be about 0.02 nmol L-1. Moreover, these PU@PDA@Ag sponges could be served as excellent flexible SERS substrates to rapidly detect trace inorganic explosives with high collection efficiency via swabbing extraction. The detection limit for perchlorates (ClO4-), chlorates (ClO3-) and nitrates (NO3-) were approximately down to 0.13, 0.13 and 0.11 ng respectively. These flexible substrates not only could drastically increase the sample collection efficiency, but also enhance analytical sensitivity and reliability for inorganic explosive, and would have a great potential application in the future homeland security fields.


Assuntos
Substâncias Explosivas/análise , Nanopartículas Metálicas/química , Poliuretanos/química , Prata/química , Compostos de Anilina/química , Materiais Biomiméticos/química , Cloratos/análise , Indóis/química , Limite de Detecção , Nitratos/análise , Oxirredução , Percloratos/análise , Polímeros/química , Reprodutibilidade dos Testes , Análise Espectral Raman/métodos , Compostos de Sulfidrila/química
11.
Anal Chim Acta ; 1077: 266-272, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31307718

RESUMO

Fluorescence quenching based immunoassay format for the detection of a trace amount of some nitro-explosives with a high degree of selectivity is reported in this study. The immunoassay comprises anti-explosive antibodies functionalized microtitre strips specific to the targeted explosives, pentaerythritol tetranitrate (PETN), 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), and 2,4,6-trinitrotoluene (TNT). UV induced photolysis of nitro-explosive bound to targeted antibodies generates primarily nitrite ions which after the quick reaction with the detector molecule, 2,3-diaminonaphthalene (DAN), a fluorophore, quenches its fluorescence intensity, however, proportionately undergo cyclization to produce a highly fluorescent product, 2,3-naphthotriazole (NAT). The synthesized product, NAT, was verified using various chromatographic and spectrophotometric techniques. This newly developed antibody-based detection method, utilizing DAN dye, demonstrated a high selectivity towards PETN, RDX, and TNT. This method can be used as an economical testing kit for direct quantification of explosives, implying the great potential for quick, low-cost trace detection of explosives.


Assuntos
Substâncias Explosivas/análise , Imunoensaio/métodos , Tetranitrato de Pentaeritritol/análise , Espectrometria de Fluorescência/métodos , Triazinas/análise , Trinitrotolueno/análise , 1-Naftilamina/análogos & derivados , Anticorpos Imobilizados/imunologia , Substâncias Explosivas/imunologia , Substâncias Explosivas/efeitos da radiação , Corantes Fluorescentes/química , Tetranitrato de Pentaeritritol/imunologia , Tetranitrato de Pentaeritritol/efeitos da radiação , Fotólise , Triazinas/imunologia , Triazinas/efeitos da radiação , Triazóis/química , Trinitrotolueno/imunologia , Trinitrotolueno/efeitos da radiação , Raios Ultravioleta
12.
Anal Chim Acta ; 1077: 1-13, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31307698

RESUMO

UV photoionization (UV-PI) is a promising non-radioactive ionization method for ion mobility spectrometry (IMS). It could work at either direct photoionization mode or chemical ionization mode by adding photoionizable dopants, and thus its applications extend to a wide range of compound classes. This work is to present a comprehensive review on the development of UV-PI-IMS. It focuses on UV-PI's capabilities and how to use them fully. A summary discussion of the ionization processes in UV-PI would be presented first for understanding the fundamentals of UV-PI-IMS. Followed by descriptions of the technical configurations of UV-PI source in IMS. Improvements in the design of UV-PI source for achieving optimum results will be presented with references to examples. Further, a broad range of applications, including environmental contaminants analysis, trace explosives and chemical warfare agents detection, food safety and quality analysis, and clinical diagnosis, would be presented to demonstrated the analytical performance of UV-PI-IMS. In the conclusion, perspectives on areas of UV-PI technique which have the potential to be improved would be reasonably presented.


Assuntos
Espectrometria de Mobilidade Iônica/métodos , Animais , Substâncias para a Guerra Química/análise , Poluentes Ambientais/análise , Substâncias Explosivas/análise , Contaminação de Alimentos/análise , Humanos , Raios Ultravioleta , Compostos Orgânicos Voláteis/análise
13.
J Chromatogr A ; 1602: 467-473, 2019 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-31178161

RESUMO

The detection and analysis of explosives and explosive-related compounds is a heightened priority in recent years for homeland security and counter-terrorism applications. This study aimed to evaluate the use of a commercial Lab-On-a-Chip (LOC) instrument for the analysis of explosive vapours, with the long-term goal of developing a portable instrument for passively detecting explosives in air samples. A simple method to collect explosive vapour residues was developed using a glass vial containing varying amounts of the target explosives (1 mg/mL). Standards were diluted to the desired concentration in 150 µL of acetone to facilitate the evaporation. The top of the vial was covered with a circular 0.5 cm diameter filter paper and exposed to a range of temperatures from 22 °C to 80 °C for 15 min. Following evaporation, the filter paper chads were folded and inserted into the LOC wells containing the separation buffer for the analysis, avoiding any further extraction step. After successfully separating and detecting eight explosives via liquid analysis, three explosives were chosen as targets for the vapour analysis experiments. 1,3,5-Trinitrobenzene (TNB), 2,4,6-Trinitrotoluene (TNT), and 2,4,6-Trinitrophenylmethylnitramine (Tetryl) were successfully separated, detected and identified following the vapour extraction of explosive standards onto filter paper chads. Limits of detection for the liquid analysis were demonstrated to be 2.32 ng for TNB, 2.35 ng for Tetryl, and 3.25 ng for TNT. The minimum detectable mass found for the vapour analysis was 6.03 for TNB, 9.99 ng for TNT, and 14.22 ng for Tetryl. The average recovery from the paper chads was 29% for Tetryl, 47% for TNB, and 75% for TNT (n = 4), comparable with findings from previous studies. Results show that a minimum temperature of 40 °C is necessary to vaporize the compounds using acetone, while the best results were achieved when heating the vial to 80 °C. The use of a filter paper to collect the explosives residues, avoiding any additional extraction step, and the ability to analyze these compounds using a LOC instrument, makes this approach a future alternative method for explosive residues detection in the headspace.


Assuntos
Substâncias Explosivas/análise , Dispositivos Lab-On-A-Chip , Nitratos/análise , Limite de Detecção , Padrões de Referência , Temperatura , Volatilização
14.
Environ Pollut ; 252(Pt A): 767-776, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31200202

RESUMO

Between 1920 and 1967, approximatively 8200 tons of ammunition waste were dumped into some Swiss lakes. This study is part of the extensive historical and technical investigations performed since 1995 by Swiss authorities to provide a risk assessment. It aims to assess whether explosive monitoring by passive sampling is feasible in lake-bottom waters. Polar organic chemical integrative sampler (POCIS) and Chemcatcher were first calibrated in a channel system supplied with continuously refreshed lake water spiked with two nitroamines (HMX and RDX), one nitrate ester (PETN), and six nitroaromatics (including TNT). Exposure parameters were kept as close as possible to the ones expected at the bottom of two affected lakes. Sixteen POCIS and Chemcatcher were simultaneously deployed in the channel system and removed in duplicates at 8 different intervals over 21 days. Sorbents and polyethersulfone (PES) membranes were separately extracted and analyzed by UPLC-MS/MS. When possible, a three-compartment model was used to describe the uptake of compounds from water, over the PES membrane into the sorbent. Uptake of target compounds by sorbents was shown not to approach equilibrium during 21 days. However, nitroaromatics strongly accumulated in PES, thus delaying the transfer of these compounds to sorbents (lag-phase up to 9 days). Whereas sampling rate (RS) of nitroamines were in the range of 0.06-0.14 L day-1, RS of nitroaromatics were up to 10 times lower. As nitroaromatic accumulation in PES was integrative over 21 days, PES was used as receiving phase for these compounds. The samplers were then deployed at lake bottoms. To ensure that exposure conditions were similar between calibration and field experiments, low-density polyethylene strips spiked with performance reference compounds were co-deployed in both experiments and dissipation data were compared. Integrative concentrations of explosives measured in the lakes confirmed results obtained by previous studies based on grab sampling.


Assuntos
Azocinas/análise , Monitoramento Ambiental/métodos , Substâncias Explosivas/análise , Triazinas/antagonistas & inibidores , Trinitrotolueno/análise , Poluentes Químicos da Água/análise , Calibragem , Cromatografia Líquida , Cinética , Lagos/química , Compostos Orgânicos/análise , Polímeros/química , Sulfonas/química , Espectrometria de Massas em Tandem , Água/química
15.
Environ Int ; 128: 371-378, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31078006

RESUMO

New Year's Eve fireworks represent one of the most unusual atmospheric pollution events in the course of a year. A majority of particles aerosolized by burning of fireworks consist of metals and their compounds used in firework displays. In this study, ambient particulate matter was sampled using a 14 stage cascade impactor in two European cities during turn of the years 2016/17 and 2017/18. Concentrations of 33 elements were determined by inductively coupled plasma mass spectrometry. To assess the impact of New Year's Eve fireworks on ambient air quality, chemically resolved size distributions of particles with diameters between 15 nm and 10 µm collected during fireworks episodes were compared to ones collected in normal winter weeks. For some metals a distinct shift of their concentration maximum related to fireworks could be observed, which is in between the maxima for accumulation and coarse mode particles. Concentrations of these elements (Sr, Ba, Mg, Bi, Al, Cu and K) were also higher during weeks with fireworks episodes than during control weeks. Although New Year's Eve fireworks only take place once a year, these results show that air pollution caused by fireworks can be a potential health risk, especially for people with pre-existing diseases.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , Monitoramento Ambiental , Substâncias Explosivas/análise , Material Particulado/análise , Áustria , Cidades , República Tcheca , Elementos , Férias e Feriados , Tamanho da Partícula
16.
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
17.
J Gen Appl Microbiol ; 65(3): 145-150, 2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-30700648

RESUMO

Explosives such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) are common contaminants found in soil and groundwater at military facilities worldwide, but large-scale monitoring of these contaminants at low concentrations is difficult. Biosensors that incorporate aptamers with high affinity and specificity for a target are a novel way of detecting these compounds. This work describes novel riboswitch-based biosensors for detecting RDX. The performance of the RDX riboswitch was characterized in Escherichia coli using a range of RDX concentrations from 0-44 µmol l-1. Fluorescence was induced at RDX concentrations as low as 0.44 µmol l-1. The presence of 4.4 µmol l-1 RDX induced an 8-fold increase in fluorescence and higher concentrations did not induce a statistically significant increase in response.


Assuntos
Técnicas Biossensoriais/métodos , Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Substâncias Explosivas/análise , Triazinas/análise , Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Medições Luminescentes , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Riboswitch/genética
18.
Org Biomol Chem ; 17(10): 2594-2613, 2019 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-30734815

RESUMO

The first tetrakis-tetrathiafulvalene-calix[4]pyrrole (TTF-C[4]P) was reported in 2004. Early on it and related π-extended TTF-C[4]Ps were found to function as both anion receptors and as hosts for planar electron deficient neutral guests, including nitroaromatic explosives. Anion binding was found to occur with a 1 : 1 binding stoichiometry and to stabilise the cone C[4]P conformation, whereas planar electron deficient guests were bound in a cooperative 1 : 2 fashion to the 1,3-alternate conformer. Addition of strongly complexing anions was found to trigger release of the electron deficient guests concurrent with a conformational change to the cone form. Subsequent studies led to the discovery of anion-induced complexation with C60, and the finding that the resulting complexes would support fast photoinduced electron transfer events. Synthetic advances then led to the preparation of nonsymmetric TTF-C[4]Ps where a single moiety organises the receptor in either the 1,3-alternate conformation or the partial cone conformation, thus modifying both selectivity and sensitivity. TTF-C[4]P-based stimulus responsive systems, that rely on anions and cations as controlling inputs, have also been developed and studied in recent years. This review provides a summary of TTF-C[4]P-related chemistry.


Assuntos
Calixarenos/química , Pirróis/química , Colorimetria/métodos , Substâncias Explosivas/análise , Substâncias Explosivas/química , Fulerenos/química , Conformação Molecular , Nitrobenzenos/análise , Nitrobenzenos/química
19.
Crit Rev Anal Chem ; 49(5): 415-438, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30672320

RESUMO

Nitrate esters-based propellant (NEBP) belongs to the main classes of energetic materials being used in civilian and military applications. These NEBPs are not highly stable, and during aging, some of their functional characteristics may change, what can lead to serious safety problems. A thorough analytical characterization of NEBP is of fundamental importance to provide an adequate support for their stability and safe life assessment. Moreover, in order to safely store and fully exploit these energetic materials, accurate analytical techniques and strategies are indispensable to efficiently judge their properties during aging. Although various methodologies have been developed worldwide to evaluate the aging behavior of NEBP, the characterization is not a simple task and often involves the combination of several techniques, whose results have to be evaluated together. This review sought to evaluate existing analytical techniques which can be utilized for a suitable analysis of NEBP stability and aging, evidencing their respective advantages and shortcomings. The employment of each examined technique is described and discussed by relevant examples from the literature.


Assuntos
Propelentes de Aerossol/análise , Ésteres/análise , Substâncias Explosivas/análise , Nitratos/análise , Cromatografia , Técnicas Eletroquímicas , Análise Espectral
20.
ACS Sens ; 4(2): 389-397, 2019 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-30672707

RESUMO

Improved sensing strategies are needed for facile, accurate, and rapid detection of aromatic and nonaromatic explosives. Density functional theory was used to evaluate the relative binding interaction energies between halogen-containing sensor model molecules and nitro-containing explosives. Interaction energies ranged from -18 to -14 kJ/mol and highly directional halogen bonding interactions were observed with bond distances ranging between 3.0 and 3.4 Å. In all geometry optimized structures, the sigma-hole of electropositive potential on the halogen aligned with a lone pair of electrons on the nitro-moiety of the explosive. The computational results predict that the strongest interactions will occur with iodine-based sensors as, of all the halogens studied, iodine is the largest, most polarizable halogen with the smallest electronegativity. Based on these promising proof-of-concept results, synthetically accessible sensors were designed using 1,4-dihalobenzene (X = Cl, Br, and I) with and without tetra-fluoro electron withdrawing groups attached to the benzene ring. These sensing molecules were embedded onto single walled carbon nanotubes that were mechanically abraded onto interdigitated array electrodes, and these were used to measure the responses to explosive model compounds cyclohexanone and dimethyl-dinitro-benzene in nitrogen gas. Amperometric current-time curves for selectors and control molecules, including concentration correlated signal enhancement, as well as response and recovery times, indicate selector responsiveness to these model compounds, with the largest response observed for iodo-substituted sensors.


Assuntos
Substâncias Explosivas/análise , Substâncias Explosivas/química , Halogênios/química , Hidrocarbonetos Aromáticos/análise , Hidrocarbonetos Aromáticos/química , Nanotubos de Carbono/química , Transporte de Elétrons , Modelos Moleculares , Conformação Molecular
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