Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 32.342
Filtrar
1.
Talanta ; 236: 122834, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34635224

RESUMO

In this study, we have developed a variable pressure operating hollow cathode discharge (HCD) ion source to investigate the gas phase ion-molecule reactions of nitroaromatic explosive compounds. The developed HCD ion source coupled MS system has also been validated as an analytical method to analyze explosives at trace levels. The ion source was designed in such a way that the plasma can be generated alternatively at high pressure (~30 Torr), medium pressure (~5 Torr) and low pressure (~1 Torr) regions. The plasma contains a sufficient amount of reactant ions, electrons and excited species, thus the gaseous analyte molecules were efficiently ionized when they passed through the plasma. In the ion-molecule reactions of the nitroaromatic explosives, the discharge products of NOx- (x = 2,3), O3 and HNO3 originating from the plasma-excited air were suggested to contribute to the formation of mostly [M - H]-, [M - NO]-, [M+NO3-HNO2]- and [M-NO+HNO3]- adduct ions at the higher ion source pressures (~5 and 28 Torr) while the electron rich plasma leads to the formation of molecular ion, M-•, at the lower ion source pressure (~1 Torr). Formation of the hydride-adduct ions of the nitroaromatic compounds reveals the surface-assisted Birch type reduction in the HCD plasma. The variety of spectral patterns in the air-assisted glow discharge would be useful for high through-put detection of TNT and TNT-related explosives. An ambient helium dielectric barrier discharge (DBD) ion source was also used and gave identical mass spectra of the nitroaromatic explosive compounds to those observed by the HCD ion source, but did not give any hydride-adduct ions of the explosive compounds. Ion formation mechanism of these ions is also discussed.


Assuntos
Substâncias Explosivas , Eletrodos , Gases , Íons , Espectrometria de Massas
2.
Talanta ; 236: 122872, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34635253

RESUMO

A conjugated microporous organic polymer (TPA-Bp) comprised of triphenylamine (TPA) and 2,2'-bipyridine-5,5'-diformaldehyde (Bp) was prepared via the Schiff-base reaction under ambient conditions. TPA-Bp is an amorphous and microporous spherical nanoparticle with very high stability. TPA-Bp suspension in DMF displayed strong fluorescence emission and selective fluorescence quenching response towards Fe3+ and Fe2+ ions. The fluorescence intensity of TPA-Bp at 331 nm presents linear relationship with the concentrations of both Fe3+ and Fe2+ with low detection limits of 1.02 × 10-5 M for Fe3+ and 5.37 × 10-6 M for Fe2+. The results of X-ray photoelectron spectroscopy (XPS) and Fourier Transform infrared spectroscopy (FTIR) confirm the selective coordination of N atoms of pyridine unit with Fe ions. The fluorescence quenching of TPA-Bp upon the addition of Fe3+/Fe2+ ions can be attributed to the absorption competition quenching (ACQ) mechanism and the energy transfer between TPA-Bp and Fe3+/Fe2+ ions. This work demonstrates that the conjugated microporous polymers are promising candidates as luminescent sensor for detection of the special analytes in practical applications.


Assuntos
Corantes Fluorescentes , Polímeros , Íons , Ferro , Espectrometria de Fluorescência
3.
J Hazard Mater ; 421: 126657, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34315023

RESUMO

The study aims to prepare a novel low-cost and environmentally friendly adsorbent by using date pits (DP) impregnated with cellulose nanocrystals (CNCs) and ionic liquid (IL), named IL-CNC@DP. The batch adsorption of lithium onto IL-CNC@DP and DP were studied at different pH values, initial lithium concentrations, and temperatures. The thermodynamics constants of the adsorption process showed that the IL-CNC@DP was exothermic, did not favor a high level of disorder, and spontaneous in nature. At pH 6, there is a significant increase in the removal efficiency where it increased to 90%. This also could be explained by the fact that electrostatic attraction forces and hydrogen bonding existed between the protonated Li+ and the less protonated IL-CNC@DP adsorbent surface, which enhanced the percentage of Li+ removal. A strong inter- and intra-hydrogen bonding (O-H) stretching absorption is seen at 3311 cm-1 that occurs in cellulose components. In conclusion, the IL-CNC@DP in comparison to the DP confirmed exceptional results proving that the modification enhanced the remediation of the Li+ from water. Furthermore, the selectivity of IL-CNC@DP towards real groundwater samples isolated in Qatar depends upon the physicochemical characteristics of each element.


Assuntos
Água Subterrânea , Líquidos Iônicos , Nanopartículas , Adsorção , Celulose , Íons , Lítio
4.
J Hazard Mater ; 421: 126722, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34332480

RESUMO

The novel sulfomethylated lignin-grafted-polyacrylic acid (SL-g-PAA) hydrogel was fabricated in this work via a facile and green synthetic strategy for the efficient removal of heavy metal ions from wastewater, and then successively reused for chemiluminescence (CL). The sulfomethylation of lignin was first performed to improve its water solubility and introduce numerous active sites for adsorption of heavy metal ions. The as-synthesized SL-g-PAA hydrogel with high content of lignin exhibited the highly efficient and rapid removal of various metal ions from simulated wastewater. More importantly, the spent hydrogel (M2+@SL-g-PAA) after adsorption was reused for the first time to develop a new CL system by an ingenious strategy, in which these metal ions adsorbed on M2+@SL-g-PAA act as heterogeneous catalytic sites to catalyze the CL reaction between N-(4-aminobutyl)-N-ethylisoluminol (ABEI) and H2O2. The resultant CL system displayed high CL intensity and long duration time, which could be observed by naked eye in the dark and lasted for > 24 h. The combination of facile fabrication process, renewable raw materials, and ingenious strategy for successive application in adsorption and CL endows this lignin-based composite hydrogel with a great potential for application in wastewater treatment, biological imaging and cold light sources.


Assuntos
Metais Pesados , Poluentes Químicos da Água , Adsorção , Hidrogéis , Peróxido de Hidrogênio , Íons , Lignina , Luminescência , Águas Residuárias , Poluentes Químicos da Água/análise
5.
J Colloid Interface Sci ; 605: 173-181, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34325339

RESUMO

A rapid, cost-effective and accurate detection of heavy metal ions is crucial for human health monitoring and environmental protection. Surface-enhanced Raman spectroscopy (SERS) has become a reliable method due to its outstanding performance for the identification of contaminants. In this paper, silver phosphate microcubes (Ag3PO4) were fabricated using two different precipitation methods for ultrasensitive SERS detection of heavy metal ions. The use of an organic linker (BPy) with Ag3PO4 enabled the immobilization of Hg2+ and Pb2+ ions. The formation of Ag3PO4 was confirmed by XRD, UV-DRS, FESEM coupled with EDX and HRTEM. The analytical enhancement factor (AEF) obtained was 1010 with a detection limit of 10-15 M indicating high sensitivity. Based on these results, the possible SERS mechanism has been proposed and discussed. Moreover, an excellent reusability of Ag3PO4 substrate for at least four cycles was achieved upon the light exposure on heavy metal loaded substrate due to its superior catalytic ability for the degradation of heavy metal ions. The as-prepared substrate demonstrated remarkable stability, selectivity and SERS sensitivity towards real samples. The results conclude that Ag3PO4 microcubes offer a great prospect in recyclable SERS applications.


Assuntos
Mercúrio , Nanopartículas Metálicas , Humanos , Íons , Fosfatos , Compostos de Prata , Análise Espectral Raman
6.
J Colloid Interface Sci ; 605: 547-555, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34340039

RESUMO

A quasi-solid-state Li-Te battery is developed by using a flexible gel polymer electrolyte (GPE), porous carbon/tellurium cathode, and lithium metal anode. The ionic conductivity of GPE is controllable and reaches up to 8.0 × 10-4 S cm-1 at 25 °C. The good interfacial contact with Li metal ensures excellent cycling stability in Li/GPE/Li symmetric cells. Moreover, it is found that, compared to S and Se counterparts, the Li-Te battery exhibits good rate capability due to the high electrical conductivity of Te and excellent interfacial stability among GPE, Li, and Te. This work provides several facile strategies to develop safe and high-performance solid-state Li-Te batteries.


Assuntos
Lítio , Telúrio , Fontes de Energia Elétrica , Íons , Polímeros
7.
J Hazard Mater ; 421: 126728, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34339990

RESUMO

The increasing release of nanomaterials has attracted significant concerns for human and environmental health. Similarly, the dissemination of antimicrobial resistance (AMR) is a global health crisis affecting approximately 700,000 people a year. However, a knowledge gap persists between the spread of AMR and nanomaterials. This study aims to fill this gap by investigating whether and how nanomaterials could directly facilitate the dissemination of AMR through horizontal gene transfer. Our results show that commonly-used nanoparticles (NPs) (Ag, CuO and ZnO NPs) and their ion forms (Ag+, Cu2+ and Zn2+) at realistic concentrations within aquatic environments can significantly promote the transformation of extracellular antibiotic resistance genes in Acinetobacter baylyi ADP1 by a factor of 11.0-folds, which is comparable to the effects of antibiotics. The enhanced transformation by Ag NPs/Ag+ and CuO NPs/Cu2+ was primarily associated with the overproduction of reactive oxygen species and cell membrane damage. ZnO NPs/Zn2+ might increase the natural transformation rate by stimulating the stress response and ATP synthesis. All tested NPs/ions resulted in upregulating the competence and SOS response-associated genes. These findings highlight a new concern that nanomaterials can speed up the spread of AMR, which should not be ignored when assessing the holistic risk of nanomaterials.


Assuntos
Resistência Microbiana a Medicamentos , Íons , Nanopartículas Metálicas , Acinetobacter/genética , Antibacterianos , Resistência Microbiana a Medicamentos/genética , Humanos , Íons/toxicidade , Nanopartículas Metálicas/toxicidade
8.
J Hazard Mater ; 421: 126801, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34388916

RESUMO

A novel chemosensor is developed for the sensitive and facile detection of trace strontium ions (Sr2+) based on the ion-imprinted hydrogels. With Sr2+ as the templates, the ion-imprinted hydrogels are synthesized by copolymerizing the ion-responsive units 5'-O-acryloyl-2',3'-O-isopropylidene guanosine (APG) and the thermo-responsive units N-isopropylacrylamide (NIPAM). In the presence of Sr2+, APG units can self-assemble to form planar G-quartets via the complexation with Sr2+, which are introduced into the gel network during polymerization. Then Sr2+ templates can be removed by multiple repeated washing. When re-exposed to Sr2+, the relaxed G-quartets can recognize Sr2+, leading to the weakening of electrostatic repulsion between the four oxygen atoms in the G-quartets and inducing the shrinkage of the hydrogels. In this work, the Sr2+-imprinted chemosensors are designed as the grating systems for detecting trace Sr2+. Based on the array of hydrogel strings synthesized on a nano-scale, the smart grating systems thus constructed can convert and amplify the Sr2+ concentration signals to the easily-measurable optical signals. With the Sr2+-imprinted hydrogel gratings, trace Sr2+ (10-11 M) in an aqueous solution can be detected sensitively. Moreover, the proposed Sr2+-imprinted chemosensors can be integrated with other smart systems for developing various detectors with high performance.


Assuntos
Hidrogéis , Estrôncio , Guanosina , Íons , Polimerização
9.
J Hazard Mater ; 421: 126828, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34396964

RESUMO

In this work, we manifested a new approach in designing solid-state colorimetric sensors for the selective optical sensing of As3+. The sensor fabrication is modulated using, (i) a cubic mesopores of ordered silica monolith, and (ii) a bimodal macro-/meso-porous polymer monolith, as hosting templates that are immobilized with a tailor-made chromoionophoric probe (DFBEP). The surface morphology and structural dimensions of the monolith templates and the sensor materials are characterized using p-XRD, XPS, FE-SEM-EDAX, HR-TEM-SAED, FT-IR, TGA, and BET/BJH analysis. The sensing components such as pH, probe content, sensor dosage, kinetics, temperature, analyte concentration, linear response range, selectivity, and sensitivity are optimized to arrive at the best sensing conditions. The silica and polymer-based monolithic sensors show a linear spectral response in the concentration range of 2-300 and 2-200 ppb, with a detection limit of 0.87 and 0.75 ppb for As3+, respectively. The real-time ion-monitoring propensity of the sensors is tested with spiked synthetic and real water samples, with a recovery efficiency of ≥99.1% (RSD ≤1.57%). The sensors act as both naked-eye optical sensors and preconcentrators, with a response time of ≤2.5 min. The molecular and photophysical properties of the DFBEP-As3+ complex are studied by TD-DFT calculations, using the B3LYP/6-31G (d,p) method.


Assuntos
Arsênio , Dióxido de Silício , Íons , Polímeros , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier
10.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120275, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34411769

RESUMO

A turn on upconversion fluorescence probe based on the combination of ~32 nm NaYF4: Yb/Tm nanoparticles and MnO2 nanosheets has been established for rapid, sensitive detection of Fe2+ ions levels in aqueous solutions and serum. X-ray diffraction (XRD), transmission electron microscopy (TEM), absorption and emission spectra have been used to characterize the crystal structure, morphology and optical properties of the samples. MnO2 nanosheets on the surface of UCNPs act as a fluorescence quencher, resulting in the quenching of the blue fluorescence (with excitation/emission maximum of 980/476 nm) via fluorescence resonance energy transfer from upconversion nanoparticles to MnO2 nanosheets. With the adding of Fe2+, upconversion fluorescence of the nanocomposites recovers due to the reduction of MnO2 to Mn2+. Because of the low background of the probe offered by upconversion fluorescence, this probe can be used for detecting Fe2+ in aqueous solutions in the range of 0.1-22 µM with detection limit of 0.113 µM. The developed method has also been applied to detect 10 µM Fe2+ ions in serum with recoveries ranging from 97.6 to 105.3% for the five serum samples. Significantly, the probe shows fast response and stable signal, which is beneficial for long-time dynamic sensing. Thus, the proposed strategy holds great potential for disease diagnosis and treatment.


Assuntos
Compostos de Manganês , Nanopartículas , Transferência Ressonante de Energia de Fluorescência , Íons , Óxidos
11.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120279, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34438118

RESUMO

A new Schiff base 2-ethoxy-3-{[(6-{[(2-ethoxy-4-hydroxy-2H-chromen-3-yl)methylidene]amino}pyridine-2-yl)imino]methyl}-2H-chromen-4-ol (CD) was synthesized as a result of the condensation of 2,6-diaminopyridine and 3-formyl chromone in 1:2 M ratio and used for cupric ions detection and characterized through FTIR, HRMS and 1H NMR spectral techniques. The sensing capability of Schiff base for cupric ions as compared to other transition metal ions was examined by absorbance and emission studies. A considerable decrease in emission intensity appeared in Schiff base in the case of cupric ions while irrelevant changes were examined for the rest of the ions. The binding stoichiometry was obtained as 1:2 for CD: Cu2+ complex intended from the job's plot which was confirmed through HRMS spectral technique. DFT calculations were carried for the confirmation of structural relationships and absorption-emission data. The Regression coefficient, Limit of detection, and Association constant were obtained as 98.7%, 1.2 × 10-6 M, and 3.26 × 104 M-1 respectively using Benesi-Hildebrand (B-H) equation. The sensing power of Schiff base CD to recognize cupric ions was unaltered by the addition of the rest of metal ions, which was authenticated through interference studies. Schiff base CD and its complex with cupric ions were found stable over an extensive time period as revealed by time-reliant studies. The data collected by pH studies revealed that the preferred pH range for detecting cupric ions by Schiff base CD was 6 to 11. The Schiff base was finally utilized for sensing cupric ions in a variety of spiked samples of water like canal water, tap water, groundwater, distilled water.


Assuntos
Cromonas , Corantes Fluorescentes , Íons , Piridinas , Espectrometria de Fluorescência
12.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120295, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34450572

RESUMO

Cerium, an abundant lanthanide element, is widely used in human industry. The accumulation of Ce4+ ion, however, will damage the environment and biological organism. Therefore, its facile detection is highly needed. Herein, we design a hybrid sensing platform consisting of carbon dots (C-dots) and bathophenanthroline-disulfonate-Fe2+ complex (Bphen-Fe2+) for trace-level determination of Ce4+. Based on inner filter effect (IFE), the red-colored Bphen-Fe2+ complex severely quenches the fluorescence of C-dots. After addition of Ce4+, Fe2+ is oxidized to Fe3+, and the colorless Bphen-Fe3+ complex generates, which weakens the IFE efficiency and leads to the fluorescence recovery of C-dots. Meanwhile, due to the decreasing amount of Bphen-Fe2+ upon Ce4+ addition, the red color of the solution gradually fades, which enables visual detection of Ce4+ by the naked eyes. Under the optimized conditions, the C-dots/Bphen-Fe2+ system realizes the fluorometric and colorimetric sensing of Ce4+ in the range of 0.5-100 and 1.9-80 µM, with the limits of detection as low as 0.5 and 1.9 µM, respectively. This method also shows high selectivity over other common ions, and has an excellent applicability for monitoring of Ce4+ in real water samples.


Assuntos
Cério , Pontos Quânticos , Carbono , Colorimetria , Humanos , Íons , Fenantrolinas
13.
Food Chem ; 368: 130499, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34496333

RESUMO

Here, we present the potential analytical applications of photochemistry in combination with fluorescence fingerprinting. Our approach analyzes the fluorescence of samples after ultraviolet light (UV) treatment. Especially in presence of metal ions and thiol-containing compounds, the fluorescence behavior changes considerably. The UV-induced reactions (changes) are unique to a given sample composition, resulting in distinct patterns or fingerprints (typically in the 230-600 nm spectral region). This method works without the need for additional chemicals or fluorescent probes, only suitable diluent must be used. The proposed method (UV fingerprinting) suggests the option of recognizing various types of pharmaceuticals, beverages (juices and wines), and other samples within only a few minutes. In some studied samples (e.g. pharmaceuticals), significant changes in fluorescence characteristics (mainly fluorescence intensity) were observed. We believe that the fingerprinting technique can provide an innovative solution for analytical detection.


Assuntos
Corantes Fluorescentes , Raios Ultravioleta , Íons , Metais , Análise Espectral
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 266: 120474, 2022 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-34689088

RESUMO

A new fluorescent sensing microtiter plate (MTP) was developed for high sensitivity monitoring of anthracene in seawater samples. For this purpose, two ternary complexes of Tb(III) ions with dibenzoylmethane and neocuproine [Tb(DBM)2(MePhen)] or with dibenzoylmethane and bathocuproine [Tb(DBM)2(PhMePhen)] were synthesized. Elemental analysis, energy dispersive X-ray analysis, X-ray diffraction, infrared and ultraviolet-visible emission, and thermal analysis were conducted on the Tb(III) complexes. The limits of detection (DL) were 0.14 and 1.05 µmol L-1 for [Tb(DBM)2(MePhen)] and [Tb(DBM)2(PhMePhen)], respectively. [Tb(DBM)2(PhMePhen)] MTP is embedded in a membrane made of cellulose acetate. The first high-throughput anthracene sensor MTP, based on [Tb(DBM)2(PhMePhen)] sensor showed a linear range, from 0.2 to 20 µmol L-1. [Tb(DBM)2(PhMePhen)] MTP was validated for accurate and precise monitoring of anthracene using gas chromatography. The selectivity of the [Tb(DBM)2(PhMePhen)] MTP toward anthracene was examined. The data indicated that [Tb(DBM)2(PhMePhen)] MTP is suitable for rapid and direct detection of anthracene.


Assuntos
Antracenos , Térbio , Íons , Água do Mar , Difração de Raios X
15.
Sci Total Environ ; 803: 149918, 2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-34482133

RESUMO

Co-sorption of metal ions and anions/ligands at the mineral-water interface plays a critical role in regulating the mobility, transport, fate, and bioavailability of these components in natural environments. This review focuses on co-sorption of metal ions and naturally occurring anions/ligands on environmentally relevant minerals. The underlying mechanisms for their interfacial reactions are summarized and the environmental impacts are discussed. Co-sorption mechanisms of these components depend on a variety of factors, such as the identity and properties of minerals, pH, species and concentration of metal ions and anions/ligands, addition sequence of co-sorbed ions, and reaction time. The simultaneous presence of metal ions and anions/ligands alters the initial sorption behaviors with promotive or competitive effects. Promotive effects are mainly attributed to surface electrostatic interactions, ternary surface complexation, and surface precipitation, especially for the co-sorption systems of metal ions and inorganic anions on minerals. Competitive effects involve potential complexation of metal-anions/ligands in solution or their competition for surface adsorption sites. Organic ligands usually increase metal ion sorption on minerals at low pH via forming ternary surface complexes or surface precipitates, but inhibit metal ion sorption via the formation of aqueous complexes at high pH. The different mechanisms may act simultaneously during metal ion and anion/ligand co-sorption on minerals. Finally, the potential application for remediation of metal-contaminated sites is discussed based on the different co-sorption behaviors. Future challenges and topics are raised for metal-anion/ligand co-sorption research.


Assuntos
Metais , Minerais , Adsorção , Ânions , Concentração de Íons de Hidrogênio , Íons , Ligantes
16.
Spectrochim Acta A Mol Biomol Spectrosc ; 266: 120408, 2022 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-34592481

RESUMO

The non-covalent interactions between graphene and aromatic fluorophores have generated highly sensitive fluorimetric turn-on sensors for various significant analytes. Herein, the supramolecular interaction between reduced graphene oxide and 7-Hydroxy-4-Methyl-8-Amino Coumarin is made use of for tracing Cu2+ at sub-zeptomole level with excellent selectivity among a collection of nineteen metal ions. The system enables quantification of the analyte in a commendably wide range, from micromolar to zeptomolar, a feature that almost all-optical sensors lack. Handy solid-state sensor strip fabricated using the above-mentioned supramolecular combination enabled visual recognition of Cu2+ions at the molecular level. Based on the chemo recognition ability of the fluorophore, multiple Boolean logic devices operating at the molecular level are proposed. By screening pertinent coumarin derivatives, it is demonstrated that the selectivity and sensitivity of the sensors of this sort are decided by the number of π- interaction centers of the fluorophores and the strength by which they interact with graphene, respectively, which will enable identification and modification of proper fluorophores for ultra-trace detection of contaminants of environmental relevance from aqueous solutions.


Assuntos
Grafite , Cumarínicos , Corantes Fluorescentes , Íons , Metais
17.
Food Chem ; 371: 131154, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34598120

RESUMO

The influence of acidity regulators and buffers on the formation of acrylamide (AA) and 5-hydroxymethylfurfural (5-HMF) in French fries and the underlying mechanism were evaluated. Prior to frying, the potato strips were dipped in the corresponding acidity regulator solutions or buffers for 30 min at room temperature. The results showed that acids inhibited AA formation, but increased 5-HMF levels. The AA level decreased and 5-HMF level increased with decreasing pH of potato strips. Interestingly, increasing concentration of acid radical ions resulted in AA increase and 5-HMF decrease, which was opposite to the acidification effect of citric acid and acetic acid. Both pH and acid radical ion were important factors for AA and 5-HMF formation. Moreover, acidity regulators might impact AA formation by acting on the generation of methylglyoxal (MGO) and glyoxal (GO) and impact 5-HMF formation by acting on the generation of 3-deoxyglucosone (3-DG).


Assuntos
Acrilamida , Solanum tuberosum , Furaldeído/análogos & derivados , Temperatura Alta , Concentração de Íons de Hidrogênio , Íons
18.
J Hazard Mater ; 422: 126793, 2022 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-34399213

RESUMO

The use of biosolids as fertilizers in agriculture can lead to the exposure of soil biota to sulfidised silver nanoparticles (Ag2S NPs), generated during the wastewater treatment procedures. Considering the crucial role of microorganisms on soil functions, we aimed to study the effects of 10 mg kg-1 soil of Ag2S NPs or AgNO3 on the soil microbiome, using an indoor mesocosm. After 28 days of exposure, Ag2S NPs induced a significant change in the soil microbiome structure, at class, genera and OTU levels. For instance, a significantly higher abundance of Chitinophagia, known for its lignocellulose-degrading activity, was observed in Ag2S NPs-treated soil toward the control. Nevertheless, stronger effects were observed in AgNO3-treated soil, over time, due to its higher silver dissolution rate in porewater. Additionally, only the AgNO3-treated soil stimulates the abundance of ammonia-oxidizing (AOB; amoA gene) and nitrite-oxidizing (NOB; nxrB gene) bacteria, which are involved in the nitrification process. Distinct variants of amoA and nxrB genes emerged in silver-treated soils, suggesting a potential succession of AOB and NOB with different degree of silver-tolerance. Our study highlights the latter effects of Ag2S NPs on the soil microbiome composition, while AgNO3 exerted a stronger effect in both composition and functional parameters.


Assuntos
Nanopartículas Metálicas , Microbiota , Amônia , Archaea , Íons , Nanopartículas Metálicas/toxicidade , Nitrificação , Oxirredução , Prata/análise , Prata/toxicidade , Compostos de Prata , Solo , Microbiologia do Solo
19.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120313, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34474223

RESUMO

Copper ion (Cu2+) is an essential part of the living organisms. Cu2+ ions play a vital role in many biotic processes. An abnormal amount of Cu2+ ions may result in serious diseases. Herein, a novel "fluorescent ON" probe NC-Cu to trace minute levels of Cu2+ ions in presence of various biological active species has been developed. Lysosomal cells targeting group (Morpholine) was added to the probe. The spectral properties of probe NC-Cu were recorded in HEPES buffer (0.01 M, pH = 7.4, comprising 50% CH3CN, λex = 430 nm, slit: 5 nm). The synthesized probe NC-Cu work based on copper promoted catalytic hydrolysis of hydrazone and shows remarkable fluorescence enhancement. The reaction of the probe with Cu2+ ions was completed within 20 min. An excellent linear relationship (R2 = 0.9952) was found and the limit of detection (LOD, according to the 3σ/slope) for Cu2+ ions was calculated to be 5.8 µM. Furthermore, NC-Cu was effectively functional in the living cells (KYSE30 cells) to trace Cu2+ ions.


Assuntos
Cumarínicos , Corantes Fluorescentes , Cobre , Íons , Espectrometria de Fluorescência
20.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120321, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34481257

RESUMO

Zn1-xMnxAl2O4:0.1 mol% Cr3+ (0.04≤x≤0.16) phosphors with single spinel phase were synthesized by using sol-gel method and the structure, optical and temperature sensing performances were reported herein. The results of X-ray photoelectron spectra indicate that the inversion defects related to octahedral Zn are reduced and the crystal field surrounding Al changes with Mn2+ doping in ZnAl2O4 lattices. Mn2+/Cr3+ co-doped ZnAl2O4 nanophosphors reveal a green emission band assigned to Mn2+ and a series of red emission peaks assigned to Cr3+, respectively. With the concentration of Mn2+ increasing, the intensity of zero phonon line (R line) assigned to Cr3+ increases, reaching the maximum at the optimal Mn2+ concentration of x=0.14. The energy transfer from Mn2+ to Cr3+ is confirmed with the energy transfer efficiency of 83%. The separation between 2E(eg) and 2E(tg) of Cr3+ is enlarged due to Mn2+ dopants giving rise to a change of crystal field. The luminous intensity ratio between two separated emission peaks at 685 nm (R3) and 689 nm (R2) reveals an obvious temperature dependence. The relative sensitivity changes from 3.7 %K-1 to 0.25 %K-1 with the temperature increasing from 80 K to 310 K, which is much larger than that of ZnAl2O4:Cr3+ nanophosphors without Mn2+, indicating its good application prospect in optical thermometry.


Assuntos
Termometria , Transferência de Energia , Íons , Temperatura , Difração de Raios X
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...