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1.
Molecules ; 25(2)2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31936773

RESUMO

Unique eleven-membered rings containing silicon, germanium, and tin were synthesized in good yields by the reactions of the corresponding 1,2-bis((2-bromothiophen-3-yl)methoxy)benzenes with (C6H5)2ECl2 where E = Sn, Ge, Si. The Sn and Ge congeners were crystallized, but the conformers that these rings crystallized in, were quite different. As confirmed by Density Functional Theory (DFT) calculations, (C28H22O2S2Sn) assumes a unique crystal structure that leaves more room around the tetrel atom as compared to the crystal structure of the corresponding Ge compound. In the latter, the central cavity is quite open, whereas in the former, one of the methylene groups can fold inwards. Another consequence is the influence on the planes of the aromatic rings flanking the heterocycle. In the Ge case, the benzene ring is folded away from the central cavity, whereas in the Sn case, it is almost parallel to the imaginary axis through the center of the ring. Thermal analysis investigations (TGA and DSC methods) of these eleven-membered rings suggested the loss of a phenyl group in the first decomposition step. The decomposition temperature decreased from the Si containing heterocycle to Ge and was lowest for the Sn containing heterocycle.


Assuntos
Germânio/química , Compostos Heterocíclicos/química , Compostos Heterocíclicos/síntese química , Modelos Moleculares , Silício/química , Estanho/química , Cristalografia por Raios X
2.
Biosens Bioelectron ; 147: 111790, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31669805

RESUMO

In this study, modified hollow titanium dioxide and SnS2 quantum dots (SnS2 QDs) were used to build a novel electrochemiluminescence immunoassay (ECLIA) for ultrasensitive detection of chloramphenicol (CAP). The titanium dioxide hollow spheres (THS) modified with polyethyleneimine (PEI) and gold nanoparticles (Au NPs) was synthesized as a probe material for the novel ECLIA, meanwhile it also could be a coreaction accelerator which could greatly improve the interaction efficiency between SnS2 QDs and S2O82-. Then the modified THS was combined with chloramphenicol antibody to form ECLIA probes, and colloidal gold synthesized as a platform for an ECLIA by ascorbic acid (AA) reduction. A competitive immunoassay strategy was used for the detection of CAP, where CAP in the sample would compete with the coating antigen for the limited antibodies. The proposed ECLIA for CAP detection exhibited high sensitivity with a wide linear range from 0.01 ng mL-1 to 100 ng mL-1 and a low detection limit at 3.1 pg mL-1. Furthermore, it could be seen from electrochemical analysis that the effect of THS on the enhancement of ECL signal is about twice as high as that of ordinary titanium dioxide. Importantly, this work not only successfully applied THS to amplify electrochemical-luminescence signal in the ECLIA, but also successfully prepared a stable and highly selective sensor for ultrasensitive detection of CAP.


Assuntos
Técnicas Biossensoriais , Cloranfenicol/isolamento & purificação , Técnicas Eletroquímicas , Nanopartículas Metálicas/química , Cloranfenicol/química , Dissulfetos/química , Medições Luminescentes , Pontos Quânticos/química , Estanho/química , Titânio/química
3.
Mikrochim Acta ; 186(12): 755, 2019 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-31707595

RESUMO

Platinum nanoparticles were loaded on CoSn(OH)6 nanocubes via a co-precipitation method. The material (NCs) is shown to be a viable peroxidase mimic that catalyzes the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by hydrogen peroxide (H2O2) to generate oxidized TMB (oxTMB) with absorption at 652 nm. The formation of the blue color can be observed in <30 s. Thus, a visual and colorimetric assay was worked out for H2O2. It has a detection limit as low as 4.4 µM and works in the 5 to 200 µM concentration range. The method was also used to detect dopamine (DA) which is found to inhibit the enzyme mimicking activity of the NCs. Hence, less blue color is formed in its presence. The respective DA assay has a linear response in the 5.0 to 60 µM concentration range and a 0.76 µM detection limit. Graphical abstractSchematic diagram of a visual colorimetric method for determination of H2O2 and dopamine (DA) with the aid of color change of 3,3',5,5'-tetramethylbenzidine (oxTMB), based on the peroxidase-like activity of Pt/CoSn(OH)6 nanocubes.


Assuntos
Colorimetria/métodos , Dopamina/sangue , Nanopartículas Metálicas/química , Benzidinas/química , Catálise , Cobalto/química , Corantes/química , Humanos , Peróxido de Hidrogênio/química , Hidróxidos/química , Limite de Detecção , Oxirredução , Peroxidase/química , Platina/química , Estanho/química
4.
Chem Commun (Camb) ; 55(87): 13148-13151, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31617549

RESUMO

Cu2ZnSnS4 nanocrystals (CZTS NCs) have been demonstrated to be effective in tumor therapy as a novel susceptible agent for microwave thermal and microwave dynamic therapy. CZTS NCs intensify the heating effect of microwaves with a significant temperature increase of about 15 °C compared to the control group and showed remarkable anti-tumor performance after 5 min of microwave irradiation. For the first time, we report the microwave absorption performance and singlet oxygen production of CZTS NCs used in microwave therapy, which reveals new opportunities for novel combined mechanisms of microwave thermal and microwave dynamic tumor therapies.


Assuntos
Antineoplásicos/uso terapêutico , Cobre/uso terapêutico , Neoplasias Hepáticas/tratamento farmacológico , Micro-Ondas , Nanopartículas/uso terapêutico , Sulfetos/uso terapêutico , Temperatura , Estanho/uso terapêutico , Zinco/uso terapêutico , Animais , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Terapia Combinada , Cobre/química , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas Experimentais/tratamento farmacológico , Neoplasias Hepáticas Experimentais/patologia , Camundongos , Nanopartículas/química , Tamanho da Partícula , Relação Estrutura-Atividade , Sulfetos/química , Propriedades de Superfície , Estanho/química , Zinco/química
5.
Mater Sci Eng C Mater Biol Appl ; 105: 110064, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31546403

RESUMO

The aim of this study was to investigate the effect of adding 1, 2 and 4% wt of cerium on the microstructure, mechanical and corrosion properties of high pressure die casting (HPDC) Mg-4Sn alloys. Microstructure analyses of the alloys were carried out using X-Ray Diffraction (XRD) and Scanning Electron microscopy (SEM). The corrosion behaviors were determined with the potentiodynamic polarization and immersion tests in Hanks Balanced Salt Solution (HBSS), which is used as the artificial body fluid. The microstructural results showed that the addition of Ce to the main alloy creates new intermetallic phases (Ce5Sn4 and MgSnCe). In addition, Ce addition provided effectively the grain refinement of the alloys. While the hardness and yield strength of the Mg-4Sn alloy enhanced continuously with increasing Ce content, the tensile strength and elongation reached up to 2% wt. The corrosion resistance of the main alloy was improved by the addition of 1% wt of Ce. However, the Ce content, which is more than 1% wt decreased corrosion resistance.


Assuntos
Ligas/química , Cério/química , Magnésio/química , Estanho/química , Microscopia Eletroquímica de Varredura , Propriedades de Superfície
6.
Molecules ; 24(19)2019 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-31547625

RESUMO

Cu2ZnSnS4 (CZTS) ink was synthesized from metal chloride precursors, sulfur, and oleylamine (OLA), as a ligand by a simple and low-cost hot-injection method. Thin films of CZTS were then prepared by spin coating, followed by thermal annealing. The effects of the fabrication parameters, such as ink concentration, spinning rate, and thermal treatment temperatures on the morphology and structural, optical, and electrical properties of the films were investigated. As expected, very thin films, for which the level of transmittance and band-gap values increase, can be obtained either by reducing the concentration of the inks or by increasing the rate of spinning. Moreover, the thermal treatment affects the phase formation and crystallinity of the film, as well as the electrical conductivity, which decreases at a higher temperature.


Assuntos
Cobre/química , Sulfetos/química , Estanho/química , Zinco/química , Aminas/química , Antineoplásicos/química , Cristalização , Tamanho da Partícula , Soluções , Propriedades de Superfície , Temperatura
7.
Mater Sci Eng C Mater Biol Appl ; 104: 109949, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499955

RESUMO

The paper presents a comparative study of the impact that TiN, ZrN and DLC nanocoatings on titanium implants have on animal organisms. The experiment lasted 602 days and used 15 laboratory animals (rabbits from the Lagomorph species). Implants, eight of each type, were implanted subcutaneously in the cervical region. The control group consisted of three animals. Over the course of the experiment, at the beginning and subsequently every 7 days, the animals had their blood drawn and analysed for parameters indicating inflammation. Once the experiment ended, a histopathological evaluation of the animals' internal organs was conducted, and the places where the implants came into contact with the tissue were also assessed. The results of the laboratory tests did not indicate any characteristics of inflammation for any of the coatings. The histopathological examination confirmed biocompatibility in all cases. This is of great importance in the case of the DLC coating, which, due to its tribological properties - a low friction coefficient - has a very high potential for application in various areas of medicine.


Assuntos
Carbono/química , Materiais Revestidos Biocompatíveis/química , Diamante/química , Estanho/química , Titânio/química , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Inflamação/tratamento farmacológico , Masculino , Teste de Materiais/métodos , Próteses e Implantes , Coelhos , Propriedades de Superfície
8.
Biosens Bioelectron ; 142: 111525, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31369944

RESUMO

In this work, a metallic composite with strong electrocatalytic property was designed by uniformly decorating Pt and Sn nanoparticles on the surface of TiO2 nanorods (Pt-Sn@TiO2). A detection scheme was then developed based on a dual signal amplification strategy involving the Pt-Sn@TiO2 composite and exonuclease assisted target recycling. The Pt-Sn@TiO2 composite exhibited an enhanced oxygen reduction current owing to the synergistic effect between Pt and Sn, as well as high exposure of Pt (111) crystal face. Initially, a Pt-Sn@TiO2 modified glassy carbon electrode produced an amplified electrochemical signal for the reduction of dissolved oxygen in the analyte solution. Next, a DNA with a complementary sequence to a streptomycin aptamer (cDNA) was immobilised on the Pt-Sn@TiO2 modified electrode, followed by the streptomycin aptamer that hybridised with cDNA. The corresponding oxygen reduction current was diminished by 51% attributable to the hindrance from the biomolecules. After a mixture of streptomycin and RecJf exonuclease was introduced, both the streptomycin-aptamer complex and the cDNA were cleaved from the electrode, making the Pt-Sn and Pt (111) surface available for oxygen reduction. RecJf would also release streptomycin from the streptomycin-aptamer complex, allowing it to complex again with aptamers on the electrode. This has then promoted a cyclic amplification of the oxygen reduction current by 85%, which is quantitatively related to streptomycin. Under optimal conditions, the aptasensor exhibited a linear range of 0.05-1500 nM and a limit of detection of 0.02±0.0045 nM streptomycin. The sensor was then used in the real-life sample detection of streptomycin to demonstrate its potential applications to bioanalysis.


Assuntos
Antibacterianos/análise , Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/instrumentação , Nanocompostos/química , Estreptomicina/análise , Titânio/química , Animais , Técnicas Eletroquímicas/instrumentação , Desenho de Equipamento , Análise de Alimentos/instrumentação , Limite de Detecção , Leite/química , Nanocompostos/ultraestrutura , Oxirredução , Oxigênio/química , Platina/química , Estanho/química
9.
J Mater Sci Mater Med ; 30(8): 91, 2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31388766

RESUMO

Customized porous titanium alloys have become the emerging materials for orthopaedic implant applications. In this work, diamond and rhombic dodecahedron porous Ti-33Nb-4Sn scaffolds were fabricated by selective laser melting (SLM). The phase, microstructure and defects characteristics were investigated systematically and correlated to the effects of pore structure, unit cell size and processing parameter on the mechanical properties of the scaffolds. Fine ß phase dendrites were obtained in Ti-33Nb-4Sn scaffolds due to the fast solidification velocity in SLM process. The compressive and bending strength of the scaffolds decrease with the decrease of strut size and diamond structures showed both higher compressive and bending strength than the dodecahedron structures. Diamond Ti-33Nb-4Sn scaffold with compressive strength of 76 MPa, bending strength of 127 MPa and elastic modulus of 2.3 GPa was achieved by SLM, revealing the potential of Ti-33Nb-4Sn scaffolds for applications on orthopaedic implant.


Assuntos
Nióbio/química , Equipamentos Ortopédicos , Próteses e Implantes , Estanho/química , Tecidos Suporte/química , Titânio/química , Ligas/síntese química , Ligas/química , Materiais Biocompatíveis , Fenômenos Biomecânicos , Força Compressiva , Módulo de Elasticidade , Manufaturas/análise , Teste de Materiais , Ortopedia , Porosidade , Próteses e Implantes/ultraestrutura , Estresse Mecânico , Propriedades de Superfície
10.
Chemistry ; 25(61): 14003-14009, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31469199

RESUMO

The systematic assembly of supramolecular arrangements is a persistent challenge in modern coordination chemistry, especially where further aspects of complexity are concerned, as in the case of large molecular mixed-metal arrangements. One targeted approach to such heterometallic complexes is to engineer metal-based donor ligands of the correct geometry to build 3D arrangements upon coordination to other metals. This simple idea has, however, only rarely been applied to main group metal-based ligand systems. Here, we show that the new, bench-stable tris(3-pyridyl)stannane ligand PhSn(3-Py)3 (3-Py=3-pyridyl) provides simple access to a range of heterometallic SnIV /transition metal complexes, and that the presence of weakly coordinating counter anions can be used to build discrete molecular arrangements involving anion encapsulation. This work therefore provides a building strategy in this area, which parallels that of supramolecular transition metal chemistry.


Assuntos
Complexos de Coordenação/química , Metais/química , Polímeros/química , Compostos de Estanho/química , Cristalografia por Raios X , Ligantes , Conformação Molecular , Estanho/química
11.
Top Curr Chem (Cham) ; 377(4): 20, 2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-31273478

RESUMO

Form a green and sustainable chemistry point of view, cross-dehydrogenative coupling (or oxidative cross-coupling) reactions have been recognized as environmentally sustainable and atom economical synthetic routes for the construction of new carbon-carbon and carbon-heteroatom bonds, since no pre-functionalization of starting materials is required. In the past few years, the direct coupling of sp-hybridized C-H bonds with heteroatom-H bonds has received much attention because of the importance of heteroatom-substituted alkynes in organic and medicinal chemistry. This review examines the recent developments in cross-dehydrogenative coupling reactions between C(sp)-H and X-H (X = N, P, S, Si, Sn) bonds, with a particular focus on the mechanistic aspects of the reactions.


Assuntos
Alquinos/química , Carbono/química , Hidrogênio/química , Hidrogenação , Nitrogênio/química , Fósforo/química , Silício/química , Enxofre/química , Estanho/química
12.
Int J Biol Macromol ; 138: 546-555, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31336118

RESUMO

In recent times, metal oxide-organic nanocomposites have received great attention because of their feasibility to wide range applications such as super capacitors, antibacterial activity, biomedical sensors, battery applications and microfluidic devices. In this work, zinc oxide-chitosan (ZnO-CS) and their novel tin zinc oxide-chitosan (Sn1-xZnxO-CS) hybrid nanocomposites successfully synthesized by a simple one-pot sol-gel reaction. The equal metal oxide ratio such as 0.5, 1.0, 1.5 and 2.0% (W/V) for zinc and tin sources with constant weight of chitosan were used to prepare the Sn1-xZnxO-CS nanocomposites. Fourier transform infrared spectroscopy results proved the formation of Sn1-xZnxO-CS nanocomposites. X-ray diffraction patterns discovered the mixed phase polycrystalline nature of Sn1-xZnxO-CS nanocomposites. Optical and luminescence properties were extensively studied for nanocomposites by UV-Vis and photoluminescence spectroscopy, respectively. The surface modification elaborately discussed with scanning electron microscope images due to incorporation of SnOx with ZnO-CS matrix. The antibacterial properties of Sn1-xZnxO-CS were tested against Escherichia coli, Salmonella Typhi and Klebseilla Pneumoniae bacterial species.


Assuntos
Quitosana/química , Nanocompostos/química , Estanho/química , Óxido de Zinco/química , Antibacterianos/química , Antibacterianos/farmacologia , Quitina/química , Luminescência , Testes de Sensibilidade Microbiana , Nanocompostos/ultraestrutura , Espectroscopia de Infravermelho com Transformada de Fourier , Relação Estrutura-Atividade , Difração de Raios X
13.
Eur J Pharm Sci ; 137: 104987, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31295547

RESUMO

According to the European Pharmacopoeia monograph 1038 (Praeparationes homoeopathicae), homeopathic preparations are produced by successive dilution and succussion steps. Dilution levels beyond Avogadro's limit, however, render specific effects implausible according to standard scientific knowledge. Accordingly, we were interested in a critical empirical investigation of preparations produced according to this monograph. Within a precursor study we developed a bioassay based on a fingerprint metabolomic analysis of Lepidium sativum seeds germinated in vitro in either homeopathic preparations or controls in a blinded and randomized assignment. Results of the precursor study were not consistent with the hypothesis that the effects of a Stannum metallicum 30x preparation are identical to placebo. In the present study we investigated the reproducibility of these effects after scrutinizing and optimizing experimental procedures. Ten independent experiments were performed in a blinded and randomized assignment in two independent laboratories. Additionally, 10 systematic negative water control experiments were performed in both laboratories to critically assess the stability of the experimental set-up. The effects of the Stannum metallicum 30x treatment were reproduced. The systematic negative control experiments did not yield false-positive results, indicating a stable experimental set-up. We thus repeatedly observed biological effects conflicting with the assumption that Stannum metallicum 30x is identical to placebo. We therefore wish to discuss whether these findings are to be considered a scientific anomaly or whether they might stimulate further investigations to clarify whether application of the European Pharmacopoeia monograph 1038 may result in pharmaceutical preparations with specific effects.


Assuntos
Germinação/efeitos dos fármacos , Lepidium , Sementes/efeitos dos fármacos , Estanho/toxicidade , Bioensaio , Cristalização , Europa (Continente) , Lactose/química , Lactose/toxicidade , Metabolômica , Preparações Farmacêuticas , Farmacopeias Homeopáticas como Assunto , Reprodutibilidade dos Testes , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Estanho/química , Água/química
14.
Mikrochim Acta ; 186(8): 501, 2019 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-31270687

RESUMO

Porous uranium oxide hollow sphere nanoparticles were synthesized in ionic liquids under hydrothermal conditions. Various precipitating agents and ionic liquids were investigated to determine their respective impact on the resultant uranium oxide morphologies. Using hydrazine hydrate as precipitating agent and N-butyl pyridinium bromide as templating agent, a porous-hollow structure was created with a surface area of 1958 m2.g-1 and an average pore diameter of 30 nm. The nanoparticles revealed high peroxidase-mimicking activity. This was evaluated by using the peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) that is catalytically oxidized by H2O2 to give oxidized TMB (oxTMB) which is blue (with an absorption peak at 652 nm). The material was used as a nanozyme for colorimetric detection of Sn2+. Meanwhile, it is found that BSA strongly improves the catalytic activity of the nanozyme, while Sn(II) inhibits its activity. Thus, a colorimetric method for Sn2+ detection was designed. The method works in the 0.5-100 µM Sn(II) concentration range and has a lower detection limit of 0.36 µM (at S/N = 3). Graphical abstract The catalytic activity of porous-hollow nano-UO2 toward the oxidation of 3,3',5,5'-tetramethylbenzidine by H2O2 is remarkably improved in the presence of bovine serum albumin, while tin(II) inhibits its activity. This finding has been applied to design a method for colorimetric quantification of tin(II) in water samples.


Assuntos
Nanosferas/química , Peroxidase/química , Estanho/análise , Compostos de Urânio/química , Benzidinas/química , Biomimética , Catálise , Colorimetria , Peróxido de Hidrogênio/química , Líquidos Iônicos/química , Porosidade , Estanho/química
15.
PLoS One ; 14(6): e0218326, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31242218

RESUMO

The origin of the tin used for the production of bronze in the Eurasian Bronze Age is still one of the mysteries in prehistoric archaeology. In the past, numerous studies were carried out on archaeological bronze and tin objects with the aim of determining the sources of tin, but all failed to find suitable fingerprints. In this paper we investigate a set of 27 tin ingots from well-known sites in the eastern Mediterranean Sea (Mochlos, Uluburun, Hishuley Carmel, Kfar Samir south, Haifa) that had been the subject of previous archaeological and archaeometallurgical research. By using a combined approach of tin and lead isotopes together with trace elements it is possible to narrow down the potential sources of tin for the first time. The strongly radiogenic composition of lead in the tin ingots from Israel allows the calculation of a geological model age of the parental tin ores of 291 ± 17 Ma. This theoretical formation age excludes Anatolian, central Asian and Egyptian tin deposits as tin sources since they formed either much earlier or later. On the other hand, European tin deposits of the Variscan orogeny agree well with this time span so that an origin from European deposits is suggested. With the help of the tin isotope composition and the trace elements of the objects it is further possible to exclude many tin resources from the European continent and, considering the current state of knowledge and the available data, to conclude that Cornish tin mines are the most likely suppliers for the 13th-12th centuries tin ingots from Israel. Even though a different provenance seems to be suggested for the tin from Mochlos and Uluburun by the actual data, these findings are of great importance for the archaeological interpretation of the trade routes and the circulation of tin during the Late Bronze Age. They demonstrate that the trade networks between the eastern Mediterranean and some place in the east that are assumed for the first half of the 2nd millennium BCE (as indicated by textual evidence from Kültepe/Kanes and Mari) did not exist in the same way towards the last quarter of the millennium.


Assuntos
Isótopos/química , Estanho/química , Grécia , História Antiga , Mar Mediterrâneo , Microscopia Eletrônica de Varredura
16.
Chemosphere ; 232: 254-263, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31154186

RESUMO

In this study, the selective adsorption performance of different Fe-Mn binary oxides (FMBOs) towards Sb(V) in the textile wastewater under different concentrations of coexisting anions, surfactants and dyes were investigated. Results showed that the influences of different anions on the Sb(V) removal followed an order of phosphate > carbonate > sulfate > nitrate > chloride. The frequently-used organic acid of acetate was found to have insignificant effect. The coexisting surfactant with sulfonic groups could have adverse effect on the removal due to sulfonic groups could compete the adsorptive sites on Fe oxides with Sb(V). While the quaternary ammonium surfactant might have minor effect. The influences of the three widely used dyes on the Sb(V) adsorption decreased in the following order: reactive black-5 >acid orange-7> disperse blue-60, which confirmed that the dyes with sulfonic groups would have relatively higher effect. The selective adsorption capacities of Sb(V) by FMBOs followed an order of FMBO3> FMBO5 >FMBO10> FMBO20>PFO. Fixed-bed column adsorption supplied useful parameters and evidently indicated that the cyclic utilization of FMBO3 was cost-efficient for practical dynamic Sb(V) removal. The Sb(V) removal by FMBO3 from real textile wastewater can simultaneously improve the removal efficiency, stabilize pH and prevent the increase of iron concentration as compared to the traditional coagulation, further demonstrating the high practical applicability of FMBO3.


Assuntos
Estanho/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Adsorção , Ânions , Compostos Azo , Benzenossulfonatos , Corantes , Ferro , Óxidos , Fosfatos , Sulfatos , Têxteis , Estanho/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise
17.
Anal Chim Acta ; 1071: 98-108, 2019 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-31128761

RESUMO

In this work, we report a sensitive and selective electrochemical sensor for the detection of dopamine (DA) neurotransmitter based on VS2-SnS2/f-MWCNT hybrids. Herein, the binary metal sulfide (VS2-SnS2) was synthesized via single step hydrothermal route and hybrids with f-MWCNT via the ultrasonication process. The as-prepared VS2-SnS2/f-MWCNT hybrids were characterized through the FESEM, EDX and elemental mapping, TEM, XPS, Raman and XRD techniques. The electrochemical performance and catalytic activity of the modified electrodes were probed using electrochemical impedance spectra (EIS), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Interestingly, DPV results exhibits an appreciable linear range from 0.025 to 1017 µM and LOD of 0.008 µM. The selectivity study was performed to prove the high selectivity of the VS2-SnS2/f-MWCNT hybrids modified electrode. Furthermore, the practical applicability of the DA sensor was scrutinized in human serum sample and rat brain sample.


Assuntos
Dopamina/sangue , Nanotubos de Carbono/química , Neurotransmissores/sangue , Sulfetos/química , Compostos de Estanho/química , Compostos de Vanádio/química , Animais , Química Encefálica , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Humanos , Concentração de Íons de Hidrogênio , Limite de Detecção , Ratos , Reprodutibilidade dos Testes , Sulfetos/síntese química , Estanho/química , Compostos de Estanho/síntese química , Vanádio/química , Compostos de Vanádio/síntese química
18.
Molecules ; 24(9)2019 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-31035407

RESUMO

In this study, the detection and quantification of multiple classes of antibiotics in water matrices are proposed using a lab-made solid phase microextraction (SPME) fiber coupled with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The lab-made fiber was prepared using a graphene oxide (G), carbon nanotubes (C), and titanium dioxide (T) composite, namely GCT, with polyacrylonitrile (PAN) as supporting material. The detected antibiotics were enrofloxacin, sulfathiazole, erythromycin, and trimethoprim. The custom-made fiber was found to be superior compared with a commercial C18 fiber. The excellent reproducibility and lower intra-fiber relative standard deviations (RSDs 1.8% to 6.8%) and inter-fiber RSDs (4.5% to 8.8%) made it an ideal candidate for the detection of traces of antibiotics in real environmental samples. The proposed validated method provides a satisfactory limit of detection and good linear ranges with higher (>0.99) coefficient of determination in the aqueous system. Application of the method was made in different real water systems such as river, pond and tap water using the standard spiking method. Excellent sensitivity, reproducibility, lower amount of sample detection and higher recovery was found in a real water sample. Therefore, the extraction method was successfully applied to the detection and quantification of multiple classes of antibiotics in different aqueous systems with satisfactory results.


Assuntos
Resinas Acrílicas , Antibacterianos/análise , Nanotubos de Carbono , Microextração em Fase Sólida , Estanho , Poluentes Químicos da Água/análise , Resinas Acrílicas/química , Adsorção , Antibacterianos/química , Monitoramento Ambiental/métodos , Nanotubos de Carbono/química , Nanotubos de Carbono/ultraestrutura , Microextração em Fase Sólida/métodos , Solubilidade , Solventes , Análise Espectral , Estanho/química , Poluentes Químicos da Água/química
19.
Food Chem ; 289: 285-291, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-30955614

RESUMO

Various metal oxides were used as co-catalysts to improve the production of alkyl lactate over Sn-Beta-P. WO3 exhibited the best promotion effect. The yield of MLA increased from 25% (6.5 g L-1) over Sn-Beta-P (0.2 g) to 52% (13.4 g L-1) over WO3 (0.1 g) and Sn-Beta-P (0.1 g) at 160 °C for 5 h and 3.1 wt% of glucose concentration. MLA yield of 38% was attained even at glucose concentration of 10 wt% and the space-time yield reached 7.1 g L-1 h-1. The action mechanism of WO3 was investigated. Fine WO3 particles adsorbed on surface of Sn-Beta-P in reaction media and decreased the silanol defects of Sn-Beta-P. This promotes retro-aldol of fructose, the rate-determining step of whole reaction, thus facilitated the formation of MLA. Kinetic studies indicate that the presence of WO3 decreased the activation energy of the retro-aldol of fructose. The binary solid WO3 and Sn-Beta-P is recyclable.


Assuntos
Glucose/metabolismo , Ácido Láctico/metabolismo , Óxidos/química , Tungstênio/química , Zeolitas/química , Catálise , Frutose/química , Frutose/metabolismo , Glucose/química , Cinética , Ácido Láctico/análogos & derivados , Estanho/química
20.
Biosens Bioelectron ; 135: 192-199, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-31026773

RESUMO

Ni-SnOx, PANI and CuO nanoparticles were synthesized on cotton fabric through chemical methods to make a new flexible high-performance non-enzymatic glucose sensor. FESEM, XRD, XPS, EDS and ATR analysis were employed to characterize the structure and the morphology of the nanomaterials. The high electrochemical performance of nickel and copper oxide and hydroxide on a conductive template leads to fabrication of a wearable and flexible cotton electrode with an excellent electrocatalytic activity to oxidize glucose. This hybrid system on the fabric as an electrode indicates a detection limit of 130 nM with wide linear range of 0.001-10 mM. The sensitivity was measured to be 1625 and 1325 µA mM-1 cm-2 for the ranges of 0.001-1 and 1-10 mM, respectively. Long-term stability, appropriate selectivity and reusability for many times make possibility for utilizing the fabricated sensor in the practical applications. The fabric is a wide linear range electrode with low detection limit to sense glucose concentration in the body fluids as well as the human blood that can be presumably suggested for designing other similar flexible types of sensor.


Assuntos
Técnicas Biossensoriais/instrumentação , Glicemia/análise , Cobre/química , Fibra de Algodão , Nanocompostos/química , Compostos de Anilina/química , Fibra de Algodão/análise , Eletrodos , Humanos , Nanocompostos/ultraestrutura , Níquel/química , Estanho/química , Dispositivos Eletrônicos Vestíveis
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