Search

Abstract: The combination of biomolecules-functionalized multiwalled carbon nanotube (MWNTs) and ionic liquid (IL) yields nanostructured biointerfaces, formed a novel kind of structurally uniform and bioelectrocatalytic activity material. Rutin was chosen as a model biomolecules to investigate the composite system. The MWNTs–Rutin–IL composite film was characterized by different methods including thermogravimetric analysis (TGA), UV–vis spectra, electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscope (SECM). A pair of well-defined quasi reversible redox peaks of rutin was obtained at the MWNTs–Rutin–IL composite film modified glassy carbon electrode (GCE) by direct electron transfer between the rutin and the GCE electrode. Dramatically enhanced biocatalytic and electrocatalytic activity was exemplified at the MWNTs–Rutin–IL/GCE electrode by the oxidized of tryptophane. The oxidation peak currents of tryptophane in such modified electrode increased linearly with the concentrations of tryptophane in the range from 8×10−8 to 2×10−5 molL−1 with a detection limit of 3.0×10−8 molL−1. The unique composite material based on biomolecules-functionalized carbon nanotube and ionic liquid have wide potential applications in direct electrochemistry, biosensors, and biocatalysis. [Copyright &y& Elsevier]

Abstract: DNA probes immobilized on a gold electrode (AuE) were employed as the primers of asymmetric PCR on the AuE. In the asymmetric PCR process, the DNA probes extended in the presence of target strands in the PCR solution. After PCR the dsDNAs were denaturalized and the target DNAs were eliminated and only the extended probes maintained on the AuE. At last the electrochemical indicator of methylene blue combined to the extended probes and the electrochemical signal of indicator was measured. This signal was higher than that of the AuE modified only by original probe. When there was no target in the PCR solution, the probe did not extend and the signal did not increase. The specific sequences of chitinase gene were detected successfully from four sorts of target with different length: oligonucleotide acid, PCR products, molecule cloning vector DNA and total genome DNA of transgenic capsicum, and the estimated detection limit were 7.3×10−12, 3.2×10−11, 5.4×10−11 and 4.1×10−10 moll−1 respectively. The regeneration of the biosensor was also tested and the results indicated that its half life was 6 times. [Copyright &y& Elsevier]

Abstract: MWNTs-IL-Gel/GCE, a glassy carbon electrode modified with multiwalled carbon nanotubes (MWNTs) and ionic liquids (IL), was developed to serve as a sensor for simultaneous determination of Hydroquinone (HQ) and catechol (CC) in this paper. The modified GCE showed two well-defined redox waves for HQ and CC in both CV and DPV with a peak potential separation of ca. 0.1V, which was large enough for simultaneous detection. The results revealed that the oxidation of HQ and CC with the enhancement of the redox peak current and the decrease of the peak-to-peak separation exhibit excellent electrocatalytic behaviors. A high sensitivity of 1.8×10−7 M with detection limits of 6.7×10−8 M and 6.0×10−8 M (S/N=3) for HQ and CC were obtained. Moreover, the constants of apparent electron transfer rate of HQ and CC at MWNTs-IL-Gel/GCE were calculated as 7.402s−1 and 8.179s−1, respectively, and the adsorption quantity of HQ and CC was 1.408×10−6 molcm−2 with chronocoulometry. The developed sensor can be applied to determinate directly of HQ and CC in aqueous solution. [Copyright &y& Elsevier]

Abstract: A novel electrochemical sensor based on molecularly imprinted polymer film has been developed for aspirin detection. The sensitive film was prepared by co-polymerization of p-aminothiophenol (p-ATP) and HAuCl4 on the Au electrode surface. First, p-ATP was self-assembled on the Au electrode surface by the formation of Au–S bonds. Then, the acetylsalicylic acid (ASA) template was assembled onto the monolayer of p-ATP through the hydrogen-bonding interaction between amino group (p-ATP) and oxygen (ASA). Finally, a conductive hybrid membrane was fabricated at the surface of Au electrode by the co-polymerization in the mixing solution containing additional p-ATP, HAuCl4 and ASA template. Meanwhile, the ASA was spontaneously imprinted into the poly-aminothiophenol gold nanoparticles (PATP–AuNPs) complex film. The amount of imprinted sites at the PATP–AuNPs film significantly increases due to the additional replenishment of ASA templates. With the significant increasing of imprinted sites and doped gold nanoparticles, the sensitivity of the molecular imprinted polymer (MIP) electrode gradually increased. The molecularly imprinted sensor was characterized by electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and cyclic voltammetry (CV). The linear relationships between current and logarithmic concentration were obtained in the range from 1nmolL−1 to 0.1μmolL−1 and 0.7μmolL−1 to 0.1mmolL−1. The detection limit of 0.3nmolL−1 was achieved. This molecularly imprinted sensor for the determination of ASA has high sensitivity, good selectivity and reproducibility, with the testing in some biological fluids also has good selectivity and recovery. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the electrochemical behaviors of rutin at the MWNTs-IL-Gel/glassy carbon electrode (GCE) were investigated. Good electrocatalysis behavior towards the oxidation of rutin with enhancement of the redox peak current and decrease of the peak-to-peak separation was demonstrated. The electrochemical parameters of rutin were calculated giving values of the charge-transfer coefficient (α) and the electrode reaction standard rate constant (k s) as 0.47 and 0.2s−1, respectively. In addition, the MWNTs-IL-Gel/GCE was characterized by different methods including electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), clay film thickness, and UV–vis spectra. The oxidation peak currents of rutin in such modified electrode increased linearly with the concentration of rutin in the range from 7.2×10−8 to 6.0×10−6 molL−1 with a detection limit of 2.0×10−8 molL−1. These results suggest that the proposed electrode can be used for sensitive, simple and rapid determination of rutin. [ABSTRACT FROM AUTHOR]

Abstract: The electrochemical behavior of hydroquinone (HQ) was studied by cyclic voltammetry at a glassy carbon electrode (GCE) modified by a gel containing multi-walled carbon nanotubes (MWNTs) and room temperature ionic liquid (RTIL) of 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6). At the modified electrode, HQ showed a pair of quasi-reversible redox peaks. The cathodic peak current value (I pc) of HQ was 9.608×10−4 A, which is 43 times larger than the one at the GCE, and 11 times larger than that of I pc at the MWNTs/GCE. Furthermore, the capabilities of electron transfer on these three electrodes were also investigated by electrochemical impedance spectroscopy (EIS), and the similar conclusion as cyclic voltammetry has drawn. Besides, we also characterized the surface morphology of the prepared composite film using the scanning electronic microscopy (SEM). The MWNTs were pulled away from the tangle in RTIL. The solvent effect of RTIL may be the reason of higher adsorption amount. [Copyright &y& Elsevier]

Abstract: The detection of DNA damage is one of the most important topics in the DNA research fields. In this paper, an electrochemical method for the detection of DNA damage by combining the layer-by-layer assembly film with adriamycin (ADM) as an electrochemical probe was developed. Firstly, the layer-by-layer {dsDNA/PEI} n film was prepared by the alternate adsorption of polycationic polyethyleneimine (PEI) and negatively charged natural DNA onto glassy carbon electrode (GCE) surface. Its electrochemical behaviors were characterized by electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV), and the optimal value of n was determined to be 2. Secondly, the {dsDNA/PEI}2 film was immersed into the solution of ADM and the {dsDNA/PEI}2–ADM was obtained. While transferred into the blank solution, the {dsDNA/PEI}2–ADM would gradually release ADM, exhibiting the good reversibility of ADM incorporation. Finally, the DNA damage induced by styrene oxide (SO) was investigated and the promising results showed that the present method can be a useful tool for the detection of DNA damage. [Copyright &y& Elsevier]

Abstract: A design for recognition of β-1,3-glucanase gene (Glu) specific sequence based on probe extension was described. The detecting probe DNA and the anchoring prober were hybridized with the same target DNA firstly, then the probes were extended by DNA polymerase reaction. After that the double strand DNA was denatured, and the extended detecting probe was immobilized on a glassy carbon electrode via nanoparticle gold (AuNP). In electrochemical detection (cyclic voltammetry, CV and differential pulse voltammetry, DPV), an increased peak current (i p) of the indicator (methylene blue, MB) was obtained compared with the probe without extension. Three differently long DNAs of Glu specific sequence were employed as the target: oligonucleotide acid, molecular cloning vector DNA and total genome DNA of transgenic capsicum. The estimated DPV detection limits for three targets of oligonucleotide, the molecular cloning vector DNA and genome DNA were 2.6×10−13, 6.0×10−13 and 8.0×10−13 moll−1 respectively. [Copyright &y& Elsevier]

5'-Thiol-derivatized specific DNA probes were added to the single primer polymerase chain reaction (asymmetric PCR) solution. In the PCR process, the DNA probes extended in the presence of target; the extended probes were then immobilized on a glassy carbon electrode (GCE) via gold nanoparticles. Finally, methylene blue and the extended probes were combined and the electrochemical signals were measured. This signal was higher than that of the GCE modified only by the original probe. When there was no target in PCR solution, the probe did not extend and the signal did not increase. The specific sequences of the β-1,3-glucanase gene were detected successfully from three targets with different length: oligonucleotide, molecule clone vector DNA, and total genome DNA of transgenic capsicum. The detection limits of 2.6 × 10-13, 7.8 × 10-13, and 9.1 × 10-13 moll-1 for oligonucleotide, molecule clone vector DNA, and total transgenic capsicum genome DNA were estimated. [ABSTRACT FROM AUTHOR]

5-[4-(3-Mercaptopropyloxy)phenyl]-10,15,20-tris (2-chlorphenyl) porphyrin was utilized for fabricating a self-assembled monolayer (SAM) on a gold electrode. Then cobalt(II) was inserted into the the monolayer by refluxing the cobalt(II) solution in which the pre-assembled porphyrin-modified electrode was immersed. The monolayers were characterized by cyclic voltammetry (CV). Oxidation and catalytic mechanisms of dopamine on the modified electrode were also investigated and elucited respectively. Catalytic currents increased linearly with dopamine (DA) concentration in the range of 1.0 × 10-9 to 2.0 × 10-3 mol/L with the correlation coefficient of 0.9989. The modified electrode can be help develop a simple, quick, sensitive, and accurate method for the determination of the biomolecules such as dopamine. [ABSTRACT FROM AUTHOR]

• The structure of n-octadecylamine is similar to functional groups of PSA and C 18. • This novel modified QuEChERS method showed great adsorptive ability. • The M-CNT/ODA nanocomposite can easily separate from the acetonitrile solution. In this work, the adoption of n-octadecylamine (ODA) functionalized magnetic carbon nanotube porous nanocomposite (M-CNTs/ODA) as cleanup agents for a modified QuEChERS method to detect pesticide residues was investigated for the first time. The properties and morphology of the M-CNTs/ODA were characterized by transmission electron microscopy, vibrating sample magnetometer and X-ray diffraction. The results confirmed that M-CNTs/ODA had an excellent ability to remove matrix interferences and reduce matrix effects compared with traditional cleanup agents. The recoveries ranged from 81.3%–96.1%, the relative standard deviations (RSDs) varied from 1.98% to 6.89% (n = 3), the limits of detection (S/N = 3) of the method for the compounds were between 0.009−0.050 mg/L in real samples. Satisfactory results were also obtained for the detection of 16 pesticides in vegetables and fruits. As a promising cleanup material, the porous M-CNTs/ODA has future application potential in detecting other organic pollutants in different samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • A dual-signal readout sensor with good sensitivity and selectivity has been developed for dopamine detection. • The study of catechol oxidase mimicking MOF nanozymes has the potential to expand the range of biomimetic MOFs. • The type of modular used in the synthesis process of MOFs can influence the activity of the final enzyme. Enzyme-simulating nanomaterials, with obvious advantages of high activity, stability and cost-effectiveness, can surrogate the complex natural enzymes and catalyze enzyme-like reactions in various harsh applications. Herein, a novel fluorescent and colorimetric dual-readout sensing platform toward dopamine detection based on pyrazolate-based porphyrinic metal-organic frameworks (MOFs) by coordination regulation strategy to improve the performance of catechol oxidase mimic enzyme activity was constructed. Specifically, BA (benzoic acid) or PA (4-Formyl-1(H)-pyrazole) was introduced as auxiliary ligands to regulate the growth mode of pyrazolate-based porphyrinic MOF materials. H 4 TPP (5,10,15,20-Tetra(1 H -pyrazol-4-yl) porphyrin) and auxiliary ligands coordinated with Cu(II), exposing Cu sites with insufficient coordination and enhancing the interaction with oxygen-active species. Benefiting from the binuclear copper center structure and the preferential adsorption of reactants in the self-reinforced interface, a highly sensitive and selective detection method for dopamine based on Cu-TPP(PA) MOF material was proposed under the intervention of H 2 O 2. The feasibility of Cu-TPP(PA) MOF in detecting dopamine in human serum samples and as a paper-based analytical device was investigated. This achievement will expand the applications of MOFs in analytical chemistry and open up a new avenue for the design of highly active and stable nano-enzymes. [ABSTRACT FROM AUTHOR]

To keep fast proliferation, tumor cells are exposed to higher oxidative stress than normal cells and they upregulate the amount of some antioxidants such as glutathione (GSH) against reactive oxygen species to maintain the balance. This phenomenon is severe in hypoxic tumor cells. Although researchers have proposed a series of treatment strategies based on regulating the intracellular reactive oxygen species level, few of them are related to the hypoxic tumor. Herein, a novel organic compound (PLC) was designed by using lysine as a bridge to connect two functional small molecules, a hypoxia-responsive nitroimidazole derivative (pimonidazole) and a pH-responsive cinnamaldehyde (CA) derivative. Then, the oxidative stress amplifying ability of PLC in hypoxic tumor cells was evaluated. The acidic microenvironment of tumor can trigger the release of CA to produce reactive oxygen species. Meanwhile, large amount of nicotinamide adenine dinucleotide phosphate (NADPH) can be consumed to decrease the synthesis of GSH during the bio-reduction process of the nitro group in PLC under hypoxic conditions. Therefore, the lethal effect of CA can be amplified for the decrease of GSH. Our results prove that this strategy can significantly enhance the therapeutic effect of CA in the hypoxic tumor cells. [Display omitted] [ABSTRACT FROM AUTHOR]

Extracellular ATP (eATP) is an important biological signal transduction molecule. Although a variety of detection methods have been extensively used in ATP sensing and analysis, accurate detection of eATP remains difficult due to its extremely low concentration and spatiotemporal distribution. Here, an eATP measurement strategy based on tetrahedral DNA (T-DNA)-modified electrode sensing platform and hybridization chain reaction (HCR) combined with G-quadruplex/Hemin (G4/Hemin) DNAzyme dual signal amplification is proposed. In this strategy, ATP aptamer and RNA-cleaving DNAzyme were combined to form a split aptazyme. In the presence of ATP, this aptazyme hydrolyzes the cleaving substrate strand with high selectivity, releasing cleaved ssDNA, which are captured by the T-DNA assembled on the electrode surface, triggering an HCR on the electrode surface to form numerous linker sequences of the HCR dsDNA product. When G-quadruplex@AuNPs (G4) spherical nucleic acid enzymes (SNAzymes) with other linkers are used as nanocatalyst tags, they are captured by HCR dsDNA through sticky linkers present on the electrode surface. An amplified electrochemical redox current signal is generated through SNAzyme-mediated catalysis of H 2 O 2 , enabling easy detection of picomole amounts of ATP. Using this strategy, eATP levels released by tobacco suspension cells were accurately measured and the distribution and concentration of eATP released on the surface of an Arabidopsis leaf was determined. [Display omitted] • Novel T-DNA-based electrochemical aptazyme sensor for detecting ATP was designed. • Signal amplification was achieved by coupling aptazymes with HCR and SNAzymes. • The method showed high selectivity and detected extracellular ATP in plants. [ABSTRACT FROM AUTHOR]

The insertion reaction mechanisms of siglet and striglet CCl2 with CH3CHO have been studied by using the OFT, NBO, CCSD(T) and AIM method. The geometries of reactions, transition state and products were completely optimized by B3LYP/6-31G(d). All the energy of the species was obtained at the CCSD(T)/6-31G(d,p) level. The calculated results indicated that all the major pathways of the reaction were obtained on the singlet potential energy surface. The singlet Cd2 can not only insert the CαH (reaction I) but also can react with CβH (reaction II). There are three main existing pathways and the products are P1 (CH3COHCCl2), P2 (CH2COHCHCl2) and P4[CHCl2CHCHOH] respectively. Reaction II happens more easily according to the energy changes and the barrier in rate-controlling step. In addition, the important geometries in domain pathways have been studied by AIM theory. And also, the energy changes of H in the inserted CH bond have been investigated. [ABSTRACT FROM AUTHOR]

Abstract: The density functional theory was employed to investigate the mechanism for the cyclopropanation reactions of samarium carbenoid with an allylic alcohol. Seven competitive reaction pathways were investigated. Analysis of the calculated results shows that the models 4 and 6 have relatively low reaction barriers which suggested that the deprotonation of allylic alcohol promoted by CH3SmCH2I plays a significant important role in the cyclopropanation reaction via a samarium carbenoid. The methylene transfer and carbometalation pathways are involved in both intermolecular and intramolecular reaction pathways. On the basis of the energetics of the reaction pathways, the methylene transfer pathway is favored over the carbometalation pathway in the whole reactions. Our computational results are in good agreement with the experimental results performed by G.A. Molander and L.S. Harring. [Copyright &y& Elsevier]

The insertion reaction mechanism of CBr2with CH3CHO has been studied by using the B3LYP/6-31G(d) method. The geometries of reactions, transition state and products were completely optimized. All the energy of the species was obtained at the CCSD(T)/6-31 G(d) level. All the transition state is verified by the vibrational analysis and the internal reaction coordinate (IRC) calculations. The results show that the propionaldehyde (HP1) is the main product of CH2 insertion with CH3CHO. The calculated results indicated that all the major pathways of the reaction were obtained on the singlet potential energy surface. The singlet CBr2 not only can insert the Cα-H [reaction 1(1)]) but also can react with CβH [reaction II(1)]. The statistical thermodynamics and Eyring transition state theory with Wigner correction are used to study the thermodynamic and kinetic characters of 1(1) and 11(1) in temperature range from 100 to 2200 K. The results show that the appropriate reaction temperature rang is 250 to 1750 K and 250 to 1600 K at 1.0 atm for 1(1) and 11(1) respectively. The rate constant and equilibrium constant are distinct in the range from 250 to 1000 K so that 1(1) more easily occurs, while the reactions are not selected in the temperature range of 1000-1600 K. [ABSTRACT FROM AUTHOR]

The insertion reaction mechanism of CBr2 with CH3CH2O has been studied by using the B3LYPI6-311G(d) and CCSD(T)/6-311G(d) at single point. The geometries of reactions, transition state and products were completely optimized. All the transition state is verified by the vibrational analysis and the internal reaction coordinate (IRC) calculations. The results show that reaction (1) is the dominant reaction path, which proceeds via two steps: i) two reactants form an intermediate (IM1), which is an exothermal re- action of 8.62 kJ · mol-1 without energy barrier; ii) P1 is obtained via the TS1 and the H-shift, in which the energy barrier is 44.53 kJ · mol-1. The statistical thermodynamics and Eyring transition state theory with Wigner correction are used to study the thermodynamic and kinetic characters of this reaction in temperature range from 100 to 2200 K. The results show that the appropriate reaction temperature ranges from 200 to 1900 K at 1.0 atm, in which the reaction has a bigger spontaneity capability, equilibrium constant (K) and higher rate constant (k). [ABSTRACT FROM AUTHOR]

Abstract: The adsorption kinetics of thiol-derivatized porphyrins (abbreviated as H2TPPO(CH2) n SH, where n =3, 4, 6, 9, 10 and 12) on gold electrode have been investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) and the intention was to study the effect of alkyl chain length and terminal group on the process of forming SAMs. The time dependence on surface coverage supported that the adsorption of H2TPPO(CH2) n SH molecules typically processes with a two-step adsorption consisting of a fast initial adsorption and a following slow reorganization. The equilibrium constant (K) for the adsorption and the Gibbs free energy (ΔG ads) of SAMs were evaluated based on the Frumkin isotherm and the interaction factor between adsorbate–adsorbate molecules was also discussed. The adsorption processes at the initial step could be satisfactorily described by simple Langmuir adsorption kinetics, irrespective of alkyl chain length of adsorbate molecule. Based on Langmuir kinetics, the adsorption rate constant was determined at the initial step for the formation of all H2TPPO(CH2) n SH–SAMs studied in this work. The rate constant value was found to decrease with increasing alkyl chain length and the unique structure of porphyrin moiety as a large terminal group had a great influence on the initial adsorption kinetics compared with that of n-alkanethiol on gold. [Copyright &y& Elsevier]

Abstract: Three orientation modes of self-assembled monolayers (SAMs) of cobalt-porphyrins on the surface of gold electrode have been prepared and tested in the electroreduction of dioxygen, such as cobalt-5-(4-aminophenyl)-10,15,20-triphenylporphyrin binding covalently to 3-mercaptopropionic acid pre-assembled on gold (Co-ATP-MPA); cobalt-tetra-[p-(3-mercaptopropyloxy)-phenyl]-porphyrin (Co-TMPP) and cobalt-tetraphenyl-porphyrin axially attached with 4-mercaptopyridine SAMs pre-assembled on gold (Co-TPP-4MPY). A cyclic voltammetric investigation was carried out in an attempt to elucidate the net reaction to the dioxygen reduction. These modes were all active in electrocatalytic reduction of dioxygen through a two-electron mechanism with hydrogen peroxide produced. By combining imidazole axial with Co-TPP and the above cobalt-porphyrin SAMs and together with by testing the multilayer cobalt-porphyrin films by reduction dioxygen, the study confirmed that the electrocatalytic properties of metalloporphyrin was directly related with the structure or orientation of porphyrin ring on the surface of the electrodes. [Copyright &y& Elsevier]

Abstract: DNA hybridization on the Aunano–DNA modified glassy carbon electrode (GCE) was investigated. The thiol modified probe oligonucleotides (SH–ssDNA) at the 5′ phosphate end were assembled on the Aunano–DNA modified GCE surface. The electrochemical response of the probe immobilization and hybridization with target DNA was measured by differential pulse voltammetry (DPV) using methylene blue (MB) as the electroactive indicator. Gold nanoparticles can be dispersed effectively on the GCE surface in the presence of calf thymus DNA. Aunano–DNA modified GCE could greatly increase the active sites and enhance the response signal during immobilization and hybridization. The hybridization amount of target DNA could be greatly increased. The linear detection range of Aunano–DNA electrode for the complementary 21-mer oligonucleotide (cDNA) was achieved from 1.52×10−10 to 4.05×10−8 molL−1. The detection limit could reach the concentration of 10−10 mol/L. [Copyright &y& Elsevier]

Abstract: The rate constant of electron transfer reaction between ferrous ion in aqueous phase and decamethyferrocene located on the adjacent aqueous phase was measured by thin layer method, a simple protocol reported recently for studying electron transfer reaction at liquid/liquid interface. Despite this large increase in overall driving force, the rate constants decrease by less than an order of magnitude compared the two reaction systems of Fe3+–DMFe and Fe(CN)6 3−–DMFe. The results demonstrate that reorganization energy may be a dominating factor on the rate of electron transfer across the interface due to the effect of the size and symmetry of reactants in aqueous. In addition, the effect of thickness of the thin layers is investigated further. [Copyright &y& Elsevier]

A porphyrin 5-(4-hydroxyethoxyphenyl)-10,15,20-tris-phenylporphyrin (HEPP) was synthesized. The voltammetric behavior of gold electrodes modified with neutral free-base and positively charged cobaltous center porphyrin films through exposed hydroxyl and pre-assembled carboxyl terminal via coupled reaction were investigated using Fe(CN)63−/4−, ascorbic acid (AA), and dopamine (DA) as probe species. The voltammetric sensing of AA at the physiological level in the presence of DA can be achieved on functionalized self-assembled monolayer (SAM) of short chain cobaltous porphyrin. The selectivity of response can be improved by introducing structural defects and positively charged center (Co2+) in monolayer modified electrode. The results showed that the current of AA anodic peak and its concentration had a linear relationship in a wide range of concentration from 4 × 10−7 to 2 × 10−2 mol L−1. The detection limit obtained by differential pulse voltammetry was 6.9 × 10−8 mol L−1. [ABSTRACT FROM AUTHOR]

Contact glow discharge electrolysis (CGDE) of two dyes, weak acid brilliant red B and weak acid flavine G, was investigated under different concentrations, temperature and mediums. From the variation of their concentration with the reaction time, it was demonstrated that the oxidation would be a first-order reaction. On the base line of UV spectra of solution in the degradation process, we deduced that two dyes underwent the oxidative degradation in CGDE. The rate constants, relevant coefficients and the decolorization degree were displayed under different conditions. [Copyright &y& Elsevier]

Absorption, fluorescence spectral and viscometric studies have been carried out on the interaction of Morin (2′,3,4′,5,7-pentahydroxyflavone, ) and its Cu complex, CuL2·2H2O [L=Morin (2′-OH group deprotonated), ] with calf thymus DNA. CuL2 shows different spectral characteristics from that of Morin in the presence of DNA. Increasing fluorescence is seen for CuL2 with DNA addition whereas decreased fluorescence is observed for Morin. Quenching fluorescence is observed for the DNA–EB system when CuL2 is added whereas slightly quenched fluorescence is seen for the DNA–EB system with Morin addition. The relative viscosity of DNA and the DNA–EB system increases with the addition of CuL2. Hypochromism and a smaller shift are observed in the UV–visible spectra of CuL2 in the presence of DNA and the denatured temperature of DNA is decreased in the presence of CuL2. The above results suggested that Morin and CuL2 can both bind to DNA, but the binding mode is different. The complex binds to DNA mainly by intercalation, while Morin binds in a nonintercalating mode. [Copyright &y& Elsevier]

Solar-driven CO 2 reduction into valuable liquid fuels with H 2 O oxidation presents a very promising approach for sustainable carbon cycle to achieve carbon neutral. The PdIn@N 3 -COF exhibits a record-high total yield of alcohols of 798 μmol g−1 (CH 3 OH 74 %, and CH 3 CH 2 OH 26 %) among the COF and MOF materials as the synergy in both the bimetallic nanocluster and cluster-framework. • Solar-driven CO 2 reduction into valuable liquid fuels with H 2 O oxidation. • A facile strategy for filling bimetallic PdIn nanoclusters into covalent organic framework. • Record-high total yield for conversion of CO 2 -to-alcohols among the framework materials. • Unique synergistic effect for conversion of CO 2 to C 2 alcohols. Solar-driven CO 2 reduction with H 2 O oxidation into liquid fuels is highly desirable for sustainable carbon cycle to achieve carbon neutral, but represents a great challenge for artificial photosynthesis. Herein, bimetallic PdIn nanoclusters are confined in a photosensitizing covalent organic framework (N 3 -COF) to facilely construct Pd x In y @N 3 -COF composites (x:y = 1:0, 0:1, 1:2, 1:1, 2:1). The resulting PdIn@N 3 -COF exhibits excellent activity for CO 2 photoreduction with H 2 O oxidation as the H+ and e− source, showing a record-high total yield of 798 μmol g-1 for producing CH 3 OH (74 %) and CH 3 CH 2 OH (26 %) among the framework materials. The synergy in both the bimetallic nanocluster and cluster@N 3 -COF contributes greatly to C C coupling and interfacial charge transfer, thus achieving excellent activity for conversion of CO 2 to C 1 /C 2 alcohols on the non-copper catalysts. This work highlights the amazing potential for constructing bimetallic nanocluster@photosensitizing supports to produce alcohols in artificial photosynthesis with H 2 O oxidation. [ABSTRACT FROM AUTHOR]

In this study, porous cage-like hollow magnetic carbon-doped CoO nanocomposite (CoO@C) was successfully synthesized using a metal-organic frameworks (MOFs) as precursor by one-step calcination method in this work. The obtained nanoporous composite showed excellent magnetic response by taking advantage of the magnetism of CoO even without the Fe 3 O 4 , making it an advanced sorbent for magnetic solid-phase extraction (MSPE). The Co-MOF and CoO@C were characterized by XRD, TGA, SEM, TEM, vibrating sample magnetometry, and FT-IR spectroscopy. Based on this, a method using CoO@C for MSPE coupled with HPLC was established for the analysis of nine polycyclic aromatic hydrocarbons (PAHs) from various real water samples. The amount of sorbent, extraction times, extraction temperature, desorption times, oscillation rate, and elution volume were optimized. Under the optimal conditions, the method had good relative standard deviations (RSDs) of 1.1%–6.5% and a satisfying linearity range of 0.5–1000 μg L−1. The low LOD and LOQ for nine PAHs were found to be 0.06–1.30 μg L−1 and 0.19–4.30 μg L−1, respectively. The experimental results indicated that the prepared nanocomposite showed excellent adsorption capacity compared to other commercial sorbents and has potential applications for the removal of hazardous pollutants from environmental samples. [Display omitted] • Porous cage-like hollow magnetic carbon doped CoO nanocomposite was synthesized by one-step method. • The novel CoO@C showed excellent magnetic response by taking advantage of the magnetism of CoO. • A method using CoO@C for MSPE coupled with HPLC was established for the determination of nine PAHs. [ABSTRACT FROM AUTHOR]

In this study, a novel and highly sensitive electrochemical method for simultaneous determination of catechol (CC) and hydroquinone (HQ) was developed, which worked at GCE modified with Nano cobalt (Nano‐Co) by electrodeposition and L‐Cysteine by electrochemical polymerization. The Nano‐Co/L‐Cysteine GCE was investigated by cyclic voltammetry (CV), SEM and EIS. The excellent conditions have been selected including supporting electrolyte, pH, accumulation time and scan rate. The calibration curves of were obtained that the linear regression equation was I=0.0734c+6×10−6 in the range of 5.8 μM to 103 μM (R2=0.9942) for CC and the linear regression equation was I=0.0566c+5×10−6 in the range of 5.8 μM to 100 μM (R2=0.9967) for HQ. The obtained detection limits of CC and HQ both were 6×10−7 M. The modified electrode was successfully applied to the simultaneous determination of CC and HQ in water samples. [ABSTRACT FROM AUTHOR]

Combining fluorescent test strip with an easy-to-access Color Recognition App on a smartphone, the direct visualization and reliable quantitative analysis of DPA was realized based on Eu3+-functionalized copper nanoclusters. • A dual-channel luminescent signal readout probe for sensitive, rapid, and on-the-spot determination of DPA was developed. • The probe demonstrated a detection limit down to 8 nM was achieved, which is far below the infectious dose of the spores. • The combination of test paper and smartphone provided a convenient approach for visual detection of DPA. • The practical application of GSH-Cu NCs/Eu3+ was successfully exploited for DPA determination in real human serum samples. 2,6-pyridinedicarboxylic acid (DPA), as a unique biomarker of Bacillus anthracis , is highly toxic at trace levels and its pollution has shown great biological threat to homeland security and public safety worldwide. Developing portable and direct read-out devices is an inevitable trend in high demand for reliable point-of-care detection of DPA. We herein report a dual-channel luminescent signal readout probe for sensitive, rapid, and on-the-spot determination of DPA. The developed probe demonstrated a detection limit down to 8 nM was achieved, which is far below the infectious dose of the spores (60 μ M). Integrated with the low-cost paper-based sensing devices fabricated by the probe, the smartphone platform installed with a Color Recognition App could accomplish visual DPA detection, which offers a great promise for the point-of-care detection with the merits of low-cost and convenient, thus opening a new pathway for the on-site self-assessment of homeland security and public safety, especially in resource-poor settings. It is believed that the proposed assay could afford experience for designing of smart chemical nose/tongue sensor in hazardous substances monitoring. [ABSTRACT FROM AUTHOR]

• The synergy between surface geometry and surface electronic structure gives bimetallic nanoparticles unique properties. • The enhanced peroxidase mimetic activity by Hg–stimulated Cr@Ag NPs was used to construct a sensitive colorimetric sensor. • The developed colorimetric assay platform exhibits satisfying performances in real water samples. Metastable precious metal nanoparticles as precursors and self-templates with uniform atomic distribution provide unlimited possibilities for the construction of nano-secondary materials. Bimetallic nanomaterials with unexpected physical and chemical properties can be fabricated through a metal ion-mediated strategy. However, the interior functionalization of metastable precious metal nanoparticles so as to achieve synergistic interaction between precursors and external ions thus enhance the performance of bimetallic nanomaterials remains a challenge. Herein, the metal ion-mediated bimetallic nanomaterials such as Cr@Ag NPs, Ni@Ag NPs, Mn@Ag NPs, Cd@Ag NPs, and Pb@Ag NPs were precisely constructed on the basic of the seeds of silver nanoparticles (Ag NPs). More importantly, the integrated bimetallic nanomaterials Cr@Ag NPs could serve as the potential mimetic-peroxidase to sensitively and rapid identify Hg2+ in TMB-H 2 O 2 systems. Furthermore, the developed colorimetric assay platform exhibits satisfying performances in real water samples. The present study opens a new horizon for the design and construct novel nanomaterials with extraordinary opto-physical and chemical properties in colorimetric sensing. [ABSTRACT FROM AUTHOR]

• CuFe 2 O 4 was uniformly doped onto MoS 2 to activate peroxymonosulfate. • Hydroxyl radicals and sulfate radicals were the major reactive oxygen species. • Efficient degradation was ascribed to the rapid decomposition of peroxymonosulfate. • Nine intermediates involving hydroxylation and open-chain or -ring were detected. By modifying copper ferrite on the surface of molybdenum disulfide (MoS 2 /CuFe 2 O 4), an excellent catalyst that can be used for interaction with peroxymonosulfate was successfully synthesized. Owing to the large number of active sites (unsaturated sulfur) on the surface of the composite material, the electron transfer and decomposition rate of the oxidant in the reaction system were significantly enhanced. The removal ability was the strongest when the molar ratio of MoS 2 /CuFe 2 O 4 was 1.5. The removal efficiency of fluoxetine reached 97.7% within 20 min, which was higher than those obtained by pure MoS 2 (38.6%) and CuFe 2 O 4 (22.1%). The free radical test and electron paramagnetic resonance analysis indicated that sulfate radicals and hydroxyl radicals were the dominant reactive oxygen species in the reaction system. In addition, in situ Raman spectroscopy revealed that peroxymonosulfate was rapidly decomposed in the composite material system. Meanwhile, the degradation products of fluoxetine were explored by high-performance liquid chromatography-tandem mass spectrometry, and a transformation pathway based on nine intermediates was proposed, mainly involving the breaking of the carbon-oxygen bond around oxygen atom, hydroxylation, and ring-opening reactions of fluoxetine and its intermediates. [ABSTRACT FROM AUTHOR]

Based on electrochemiluminescence resonance energy transfer (ERET) from Ru(bpy) 3 2+ to graphene oxide (GO), a novel label-free solid-state ECL sensor for sensitive detection of DNA was proposed. First, Ru(bpy) 3 2+/AuNPs was successfully prepared by using a simple and green method and characterized by transmission electron microscopy (TEM), Energy Dispersive X-ray (EDX), and UV–vis spectroscopy. Then, the Ru(bpy) 3 2+/AuNPs colloid was assembled on the gold electrode surface for solid-state ECL film which also later could be used to immobilize thiol-derivatized, single-stranded DNA (HS-ssDNA) via Au–S interactions. The stepwise modification procedure was characterized by cyclic voltammetry(CV), electrochemical impedance spectroscopy (EIS), probe approach curves (PAC) and ECL, respectively. The resulting modified electrode was tested as ECL biosensor for DNA detection. Upon addition of GO, the strong noncovalent interaction between HS-ssDNA and GO led to ECL quenching because of ERET. When in the presence of target ssDNA (t-ssDNA), the distance between the HS-ssDNA and GO increased, which significantly hindered the ERET and, thus, resulted in the restoration of ECL. The ECL intensity of the biosensor increased linearly with t-ssDNA concentration in the range of 50–1000pM, and the detection limit is 20pM. To the best of our knowledge, this is the first application of solid-state ERET from Ru(bpy) 3 2+ to GO and opens new opportunities for sensitive detection of biorecognition events. First, Ru(bpy) 3 2+/AuNPs was successfully prepared by using a facile and green method. Then, directly coating the as-prepared colloid on the surface of Au electrode surface produces a solid-state ECL film which later was used to label HS-ssDNA indirectly. Upon addition of GO, due to the strong noncovalent interaction between the HS-ssDNA and GO, the ECL of Ru(bpy) 3 2+ was efficiently quenched because of ERET. In the presence of target ssDNA (t-ssDNA), the binding between the HS-ssDNA and t-ssDNA disturbed the interaction between the HS-ssDNA and GO, the distance between the HS-ssDNA and GO increased, which significantly hindered the ERET and, thus, resulted in the restoration of Ru(bpy) 3 2+ ECL. Image 1 • A novel label-free solid-state ERET platform for detection of DNA was proposed. • A facile and green method to synthetize Ru(bpy) 3 2+/AuNPs was proposed for the first time. • Probe DNA and target DNA both do not require prior labeling. • The method has high quenching efficiency, stablity, and good specificity. [ABSTRACT FROM AUTHOR]

We systematically explore the shape-dependent catalytic activities of Au nanocrystals toward glucose oxidation in alkaline electrolytes, which is strongly dependent on the shape of the Au nanocrystals. The {100}-bounded cubic Au nanocrystals are significantly more active than the {110}-bounded rhombic dodecahedral and {111}-bounded octahedral Au nanocrystals. [ABSTRACT FROM AUTHOR]

Zn (II)-imidazole derived metal azolate framework materials were synthesized via rapid solvent reaction and developed as an effective adsorbent for solid-phase microextraction of trace sixteen polycyclic aromatic hydrocarbons (PAHs) from real samples prior to their determination by HPLC. The adsorbent was characterized by Fourier transform infrared spectrometry, X-ray diffractometry, Scanning electron microscopy, Thermal gravimetric analysis and Nitrogen adsorption-desorption. An orthogonal array design (OAD) was carried out to evaluate the variables affecting extraction efficiency. Under the optimum conditions, the proposed method showed low limits of detection (LOD, 0.006–0.54 μg L−1), wide linear ranges (0.02–2000 μg L−1), and good repeatability (the relative standard deviation (RSD) is 0.11%–4.93% for single fiber and 0.42%–7.36% for fiber-to-fiber). The spiked recoveries at two levels of 20.0, 50.0 μg L−1 were in the range of 76.5%–112.0% with the RSDs less than 8.3%. Compared with commercial fibers and other reported methods, the homemade fiber displayed excellent extraction capacity. The MAF-6 coating was stable over 120 successive cycles of extraction/desorption without significant loss of extraction efficiency. The method was successfully applied for the determination of sixteen PAHs in real samples. Image 1 • Zn (II)-imidazole derived metal azolate framework were synthesized by rapid solvent reaction method. • The obtained MAF-6 materials was introduced into solid phase microextraction (SPME) adsorbent. • The MAF-6-SPME-HPLC method was successfully applied for the analysis of sixteen PAHs in real samples. [ABSTRACT FROM AUTHOR]

• Combined pollution of sulfamethoxazole and naproxen was efficiently removed. • Eubacterium spp. with abundances of over 40.00% dominated in all the samples. • Combined pollution promoted the occurrence of anti-multidrug microbes more readily. • Combined pollution increased the diversity and total abundance of ARGs and MGEs. • Salinity reduced anti-multidrug microbes and the overall abundance of ARGs. Combined pollution of antibiotic and non-antibiotic pharmaceutical residues is ubiquitous in realistic polluted environments, which is regarded as a complicated emerging pollution. Herein, high-throughput sequencing and high-throughput quantitative PCR were applied to profile the overall changes in microbial communities and antibiotic resistance genes (ARGs) of biofilms in response to a combination of naproxen and sulfamethoxazole pollution. After continuous operation for 120 days, naproxen or/and sulfamethoxazole were efficiently removed, and the salinity of 1.00% enhanced the removal rate of sulfamethoxazole. The high-throughput sequencing revealed that Eubacterium spp. with abundances of over 40.00% dominated in all samples, and combined pollution of naproxen and sulfamethoxazole more readily promoted the occurrence of multidrug-resistant microbes, including Pseudomonas and Methylophilus. The high-throughput quantitative PCR results showed that the combined pollution of naproxen and sulfamethoxazole increased the total abundance of ARGs to approximately 9 copies per cell. In contrast, increasing the salinity to 1.00% greatly reduced the overall abundance of ARGs to below 2 copies per bacterial cell. Mantel test and Procrustes analysis indicated that microbiomes from different treatments had tight links to their respective antibiotic resistomes. Furthermore, network analysis revealed that multidrug-resistant microbes were potential hosts for greatly enriched numbers of ARGs in the combined treatment. As increased salinity eliminated those multidrug-resistant but salt-sensitive microbes, the abundance of ARGs was significantly decreased. These results showed the high probability of the transmission of ARGs in biofilms exposed to combined pollution of naproxen and sulfamethoxazole, which could be relieved by increased salinity. [ABSTRACT FROM AUTHOR]

• A simple strategy for converting traditional colorimetric sensor into enhanced thermometric sensors is proposed. • A color-to-thermal signal readout conversion for breaking the low color resolution of colorimetric sensor is demonstrated. • A simple and green strategy without any additions for accomplishing color-to-thermal signal readout conversion is explored. • POCT affordable detection method by facilely mixing commercial chemicals is presented. Traditional colorimetric sensors often suffer from the low color resolution and the not well-defined boundary between the yes and no answers, especially for distinguishing the similar color readouts with the naked eye. Herein, a simple strategy is communicated for greenly converting colorimetric sensor into a photothermal sensor, which is based on the simple color-to-thermal (temperature) signal readout conversion. The colorimetric system based on simply mixing commercially available chemicals of 3,3,5,5-tetramethylbenzidine (TMB) and silver ions (Ag+), provides a straightforward blue color readout owing to the generation of oxidized TMB (TMBox). In the presence of the target alkaline phosphatase (ALP), ascorbic acid phosphate (AAP) in the system could be hydrolyzed into ascorbic acid (AA), subsequently reducing the blue colored TMBox into colorless TMB. The blue-to-colorless change-based colorimetric system also exhibits the highly sensitive near-infrared (NIR) laser-driven photothermal response, allowing the successful thermometer-detectable signal-based assay for point-of-care testing (POCT) of ALP levels just using a common thermometer. This study not only demonstrated a regulatory strategy to convert color-based signal readout into thermal (temperature)-based signal readout, but also established a facile method to design affordable thermometric sensors for POCT and instrument-free bioanalysis, especially in low-resource settings. [ABSTRACT FROM AUTHOR]

• First use of conjugated organic microporous polymers to build a novel peroxynitrite anion sensors. • The sensor showed an excellent performance in a wide range of four orders of magnitude and a super low detection limit (1.54 ± 0.5 nM). • Direct electrochemical measurements of peroxynitrite anion released from cells, • Explored the ability of antioxidants (especially reduced glutathione) to protect cells in an oxidative stress environment for the first time. • Effective differentiation and quantification of ROS and RNS in cells. The aberrant expression levels of reactive oxygen and nitrogen species (ROS and RNS) in human cells are related with many diseases, including cancer. In recent years, the primary RNS, peroxynitrite anion (ONOO−), has aroused immense research interest in the biological and biomedical fields. Herein, we build a novel sensing platform by the hollow tubular organic conjugated microporous polymer (HTCMPs) modified glassy carbon electrode (GCE) for directly monitoring of ONOO−. Specifically, the HTCMP was used to develop an electrochemical sensor for the first time. This as-prepared amperometric sensor showed an excellent activity toward the oxidation of ONOO− with a wide range of four orders of magnitude and a super low detection limit reached 1.54 ± 0.5 nM (S/N = 3). With these properties, the sensor was used for measuring the ONOO− released from glioma cells (U87) during oxidative stress induced by biochemical reagent stimulation. For the more, a new strategy to verify antioxidant protection was developed by stimulating cells at low or high doses of stimulus in a vitro simulation environment. The results showed that reduced glutathione (GSH) had great protective effect on cells in the case of oxidative stress. Last but not least, based on a battery of control tests, the concentrations of two key ROS/RNS (H 2 O 2 , ONOO−) in the cells were determined. This study essentially offers a reproducible platform for assessing the oxidative stress metabolites (ROS/RNS) in a vivo assays. [ABSTRACT FROM AUTHOR]

• 3D Fe-Mn-O NSs/WC hybrid is constructed for Fenton-like oxidation. • Surface properties of Fe-Mn-O NSs are improved by doping alien-metal ions. • The catalyst shows good activity due to synergy effect of nanosheet and carrier. • Fe-Mn-O NSs/WC can be extended to a filter membrane for flowing water treatment. Cost-effective, highly efficient and conveniently recycled heterogeneous catalyst is urgently desirable for wastewater treatment. Wood-derived monolith offers new opportunity because of its toilless functionalization and flexible processing. Herein, ferrum manganese oxide nanosheets (Fe-Mn-O NSs) were successfully grown on the microchannels of carbonized wood to construct a novel 3D wood-derived block for efficient wastewater treatment. The wood carbon not only acts as a 3D substrate to support Fe-Mn-O NSs, but also contributes to unimpeded mass diffusion benefiting from the numerous open channels and hierarchical pores on channel walls. More importantly, except for the exposure of sufficient active sites, several important surface properties (i.e. surface defects, surface charge, low-valence metal concentration and charge transfer) were improved by doping alien-metal element, resulting in greatly improved Fenton activity and stability. Notably, due to flexible processing of wood carbon, this block catalyst can be extended to filter membrane for removing pollutants in flow wastewater. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) water splitting, as a promising route of STH(solar to hydrogen) conversion, has attracted a lot attention recently. However, the rather high recombination and the low transfer rate of photoinduced electron-hole pairs restrict the applications. In this work, n-ZnO/p-CuS photoanodes were fabricated using hydrothermal method and successive ionic layer adsorption and reaction (SILAR) method. The PEC performance of the ZnO photoanode is significantly improved after depositing CuS. The applied bias photon-to-current efficiency (ABPE) of ZnO/CuS 10 (the cycles of SILAR) photoanode attained 0.368% at a bias of 0.984 V vs SCE which is 45 times than ZnO. The relatively high value of photocurrent density and ABPE are due to the advantages of the ordered structure of ZnO nanorods arrays and the common effect comes from the formation of heterojunction and faster transfer rate of photogenerated electrons which further facilitate charge carrier separation and the light absorption. This work represents a facile strategy using low cost CuS for PEC water splitting that can be applied in photocatalysis. • ZnO/CuS photoanode was successfully prepared by facile method. • ZnO/CuS photoanode showed high PEC performance. • The migration of photoinduced electrons was improved. • ZnO/CuS and ZnO/Cu 2 S heterojunctions enhanced the separation of charge carrier. [ABSTRACT FROM AUTHOR]

• The evolution of noble metal nanoparticles colorimetric sensors was proposed. • The origins of noble metal nanoparticles colorimetric sensors are reviewed. • The advances of noble metal nanoparticles colorimetric sensors are summarized. Noble metal nanoparticles as color labels and signal generators have been widely accepted for the fabrication of colorimetric assays and sensors due to their simplicity and practicality. In the past, organic dye probes and interparticle distance-dependent nanocolorimetric sensors have witnessed great progress in chem/biosensing and recognition events. However, they often suffer from a low color resolution due to the inherent low extinction coefficients of organic dyes probes and the monocolor change-based signal readout. Currently, target-dependent in situ growth of noble metal nanoparticles provides a general means to follow naked-eye-detectable color readouts with high resolution, further allowing great advances in the development of monocolorimetric and multicolorimetric sensors for different target analytes in various detection areas, such as modern bioanalysis, environmental monitoring, food analysis and clinical diagnosis. However, reviews exploring the color readout classifications, signal generation and amplification mechanisms, as well as providing guidance on the progress of such noble metal nanoparticle growth-based colorimetric assays have rarely been reported. To highlight the significant advances in this newly-developing noble metal nanoparticle morphology/size-dependent colorimetric assays field, we herein exclusively summarise the sensing fundamentals, development evolution and cutting-edge applications of this emerging field. Finally, we provide general guidance on how to design such assays on the basis of their current challenges and future perspectives. [ABSTRACT FROM AUTHOR]

It is highly desirable to develop durable photocatalysts for efficiently boosting water splitting, but it is challenging for CdS to realize the expected result without using any hole sacrificial agents. Herein, improved photocatalytic hydrogen evolution and enhanced stability are simultaneously realized in the absence of any sacrificial agents by introducing Zinc 5‐, 10‐, 15‐, 20‐meso‐tetra (4‐hydrazidephenyl) porphyrin (ZnTHPP) onto CdS nanosheets (CdS NSs). In this system (ZnTHPP/CdS NSs), a novel hole transfer channel is achieved by an internal chemical reaction using the functional group of acylhydrazine in ZnTHPP. Compared with CdS NSs, the ZnTHPP/CdS NSs exhibit excellent photostability (15 h) and efficient photocatalytic activity for pure water splitting (≈6.4 times). Furthermore, it is found that the rate constant for photogenerated holes is about 1.7 times higher than the pure CdS NSs under light irradiation. This suggests that the promising charge transfer channel can efficiently suppress charge recombination and photocorrosion of pure CdS NSs. The pattern via internal charge transfer channel not only can solve the stability of CdS based materials, but also design more semiconductors for efficient photocatalytic water splitting. [ABSTRACT FROM AUTHOR]

To realize selective separation of important small molecules in organic solvents with high permeability is highly desired but not attained yet, because it requires stringent control over selectivity in nanofiltration membranes. Here, a thiophene‐containing conjugated microporous polymer membrane, in which the pore size is finely tuned at the angstrom scale through postoxidation of the thiophene moieties, is reported. The successful modification is confirmed by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and water contact angle, leading to obvious pore size reduction evidenced by nitrogen adsorption. Upon postmodification, the selectivity of the membrane can be effectively controlled. In the pristine membrane, the methanol permeance reaches 32 liters per square meter per hour per bar (L m−2 h−1 bar−1) with a molecular weight cut‐off (MWCO) of 800 g mol−1. Significantly, after in situ postmodification of thiophene moieties, the largest pore size is reduced from 1.73 to 1.48 nm, giving rise to a remarkable decrease of MWCO from 800 to 500 g mol−1, while the permeance of methanol still maintains as high as 21 L m−2 h−1 bar−1. [ABSTRACT FROM AUTHOR]

A sensor is described for determination of superoxide anion (O2˙−). The electrode consists of nitrogen-doped cotton carbon fiber (NCFs) modified with silver nanoparticles (AgNPs) which have excellent catalytic capability. The resulting sensor, best operated at working potentials around −0.5 V (vs. SCE), can detect O2˙− over an extraordinarily wide range that covers 10 orders of magnitude, and the detection limit is 2.32 ± 0.07 fM. The electrode enables the release of O2˙− from living cells under normal or under oxidative stress conditions to be determined. The ability to scavenge the superoxide anions of antioxidants was also investigated. In the authors' perception, the method represents a viable tool for studying diseases related to oxidative stress.Schematic presentation of the construction of an electrochemical sensor based on Nitrogen-doped cotton carbon fiber and silver nanoparticles. It can be used for the direct detection of superoxide anions released from Glioma cells (U87) under normal or under oxidative stress conditions. [ABSTRACT FROM AUTHOR]

The title compound is prepared by solid state reaction of a stoichiometric mixture of PbO, Ba(NO3)2, and H3BO3 (400 °C for 10 h and 655 °C for 48 h). [ABSTRACT FROM AUTHOR]