Xiaoya Hu

Yangzhou University, Wu-hsien, Jiangsu Sheng, China

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Publications (134)438.59 Total impact

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    ABSTRACT: An electrochemical sensor for paracetamol based on multi-walled carbon nanotubes and chitosan–copper complex (MWCNTs/CTS–Cu) was fabricated by self-assembly technique. The MWCNTs/CTS–Cu modified GCE showed an excellent electrocatalytic activity for the oxidation of paracetamol, and accelerated electron transfer between the electrode and paracetamol. Under optimal experimental conditions, the differential pulse peak current was linear with the concentration of paracetamol in the range of 0.1–200 μmol L−1 with a detection limit of 0.024 μmol L−1. The sensitivity was found to be 0.603 A/mol L−1. The proposed sensor also showed a high selectivity for paracetamol in the presence of ascorbic acid and dopamine. Moreover, the proposed electrode revealed good reproducibility and stability. The proposed method was successfully applied for the determination of paracetamol in tablet and human serum samples.
    Talanta 11/2015; 144. DOI:10.1016/j.talanta.2015.06.020 · 3.51 Impact Factor
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    ABSTRACT: Hierarchical porous titanium dioxide (hp-TiO2) was prepared using natural magnolia grandiflora petals as templates and was further employed for the immobilization of horseradish peroxidase (HRP). Scanning electron microscopy (SEM) and nitrogen adsorption–desorption measurement revealed the wrinkled and porous structure of the obtained hp-TiO2. Fourier transform infrared spectroscopy (FT-IR) indicated the effective immobilization and conformation retention of HRP on hp-TiO2. HRP immobilized on hp-TiO2 exhibited direct, reversible, and surface-controlled redox reaction with the electron transfer rate constant of 5.46 s−1. Furthermore, the immobilized HRP exhibited a wide linear detection range from 1.0 to 524.0 µM. The detection limit, based on a signal-to-noise ratio of 3, was down to 0.87 µM. The apparent Michaelis–Menten constant ( ) of the immobilized HRP was 0.223 mM. In addition, the sensor possessed appreciable repeatability, reproducibility and remarkable stability for the sensitive determination of H2O2. Thus, this kind of hp-TiO2 can be used as an attractive material for immobilizing proteins and constructing biosensors.
    Talanta 11/2015; 144. DOI:10.1016/j.talanta.2015.05.081 · 3.51 Impact Factor
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    ABSTRACT: A novel magnetic metal organic frameworks adsorbent modified with mercapto groups was synthesized and developed for extraction and spectrophotometric determination of trace lead. The adsorbent was characterized by Fourier transforms infrared spectrometer, X-ray diffraction, scanning electron microscopy and vibrating sample magnetometry. The results indicated the adsorbents exhibited high adsorption capacities for lead due to the chelation mechanism between metal cations and mercapto groups. Meanwhile, the lead sorption onto the adsorbents could be easily separated from aqueous solution using a magnetic separation method. Under the optimal conditions, a linear calibration curve in the range from 1 to 20μgL(-1) was achieved with an enrichment factor of 100. The limits of detection and quantitation for lead were found to be 0.29 and 0.97μgL(-1), respectively. The developed method was successfully applied to the determination of trace amounts of lead in food samples and certified reference material with satisfactory results. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Food Chemistry 08/2015; 181. DOI:10.1016/j.foodchem.2015.02.080 · 3.39 Impact Factor
  • Zhanjun Yang · Yue Cao · Juan Li · Juntao Wang · Dan Du · Xiaoya Hu · Yuehe Lin
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    ABSTRACT: A new label-free chemiluminescence (CL) immunoassay method is proposed for the cheap, convenient and sensitive detection of proteins through the co-immobilization of a capture antibody and horseradish peroxidase on a sensing interface. The specific immunoreaction on the interface effectively inhibits the enzymatic CL reaction, thus causing a decrease in CL signals.
    Chemical Communications 08/2015; DOI:10.1039/c5cc05337d · 6.83 Impact Factor
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    ABSTRACT: In this paper, a label-free electrochemical impedance immunosensor for the detection of carbofuran was prepared by immobilizing l-cysteine on a gold electrode. The carbofuran antibodies were immobilized on the electrode by the using glutaraldehyde as a cross linker. The stepwise assembly of the electrode surface was confirmed by atomic force microscope (AFM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under the optimized conditions, a linear relationship between the resistance change and the logarithm value of carbofuran concentration was obtained in the carbofuran concentration range of 1.0 × 10−1 – 1.0 × 103 ng/mL, with a detection limit of 1.0 × 10−1 ng/mL. The immunosensor performed good reproducibility and stability. Additionally, the proposed method can be applied for monitoring carbofuran residual in agricultural and environmental samples.
    Food Control 07/2015; 53. DOI:10.1016/j.foodcont.2015.01.009 · 2.82 Impact Factor
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    ABSTRACT: We describe a highly sensitive electrochemical enzymatic glucose biosensor. A glassy carbon electrode was modified with cylinder-shaped titanium dioxide nanorods (TiO2-NRs) for the immobilization of glucose oxidase. The modified nanorods and the enzyme biosensor were characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, electrochemical impedance spectroscopy and cyclic voltammetry. The glucose oxidase on the TiO2-NRs displays a high activity and undergoes fast surface-controlled electron transfer. A pair of well-defined quasi-reversible redox peaks was observed at −0.394 and −0.450 V. The TiO2-NRs provide a good microenvironment to facilitate the direct electron transfer between enzyme and electrode surface. The biosensor has two linear response ranges, viz. from 2.0 to 52 μM, and 0.052 to 2.3 mM. The lower detection limit is 0.5 μM, and the sensitivity is 68.58 mA M−1 cm−2. The glucose biosensor is selective, well reproducible, and stable. In our perception, the cylindrically shaped TiO2-NRs provide a promising support for the immobilization of proteins and pave the way to the development of high-performance biosensors. Graphical Abstract A novel and efficient electrochemical biosensor is presented for highly sensitive detection of glucose based on the immobilization of glucose oxidase on a cylinder-shaped TiO2 nanorod-modified electrode
    Microchimica Acta 07/2015; 182(9-10). DOI:10.1007/s00604-015-1519-3 · 3.72 Impact Factor
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    ABSTRACT: In this work, we illustrate how to anchor -SO3H functional groups onto the pore surface of MOF for cadmium removal from aqueous solution via the approach of sequential post-synthetic modification and oxidation as exemplified in the context of functionalizing the MOF, Cu3(BTC)2 with sulfonic acid. The resultant sulfonic acid functionalized MOF, Cu3(BTC)2-SO3H demonstrates a high cadmium uptake capacity of 88.7 mg/g, surpassing that of the benchmark adsorbents. In addition, it exhibits a fast kinetics with the kinetic rate constant k2 of 0.6818 g/mg/min, which is 1~3 orders of magnitude higher than existing adsorbent materials for adsorbing cadmium ions from aqueous solution. Moreover, it demonstrates high selectivity of cadmium ions in the presents of other background metal ions, and can be readily regenerated and recycled without significant loss of cadmium uptake capacity. Our work thus paves a way for developing functionalized MOFs as a new type of platform for removing cadmium from wastewater.
    06/2015; 3(29). DOI:10.1039/C5TA03201F
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    ABSTRACT: Ubiquitin-like with PHD and ring finger domains 1 (UHRF1), known as ICB90 or Np95, has been found to be overexpressed in numerous cancers. In this study, we evaluated the expression level of UHRF1 in ovarian cancer. UHRF1 levels in paired ovarian cancer tissues and adjacent normal tissues from 80 ovarian cancer patients were detected using relative quantitatively PCR and Western blot. Small interfering RNA (siRNA) was introduced in two human ovarian cancer cell lines (SKOV-3 and OVCAR-3) to downregulate the expression of UHRF1. The proliferation of siRNA-treated cells was examined using cell counting kit-8 (CCK-8) assay. The growth of these cells showed a remarkable decrease. Moreover, flow cytometric and Hoechst 33342 assays were used to detect the apoptosis. The diagnostic value of UHRF1 messenger RNA (mRNA) expression in ovarian cancer was estimated by receiver-operator characteristic (ROC) curve. The correlation between UHRF1 mRNA expression and clinicopathologic features of ovarian cancer patients was evaluated by χ 2 test. Our results demonstrated that both UHRF1 mRNA and protein were highly expressed in ovarian cancer tissues and significantly higher than that in adjacent normal tissues. Moreover, the inhibition of UHRF1 may lead to cells to undergo apoptosis. Thus, UHRF1 could act as a new oncogenic factor in ovarian cancer and be a potential molecular target for ovarian cancer gene therapy.
    Tumor Biology 06/2015; DOI:10.1007/s13277-015-3638-1 · 3.61 Impact Factor
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    ABSTRACT: A simple cyclic voltammetric method has been applied to assemble and orient a model protein, Myoglobin (Mb), into a biocompatible Brij 56 film. Ultra-visible (UV-vis) and circular dichroism (CD) spectra indicated that Mb in Brij 56 matrix preserved its secondary structure. Fourier transform infrared spectra (FT-IR) confirmed the formation of hydrogen bonds between Mb and Brij 56. These hydrogen bonds were acted as the electron tunnel to transfer electrons from Mb's active sites to the underlying glassy carbon electrode. Effective direct electron transfer (DET) of Mb was realized with the presence of a couple of quasi-reversible and well-defined redox peaks at -310 mV (vs. SCE) in the studied potential range. The peaks were attributed to the redox couple of heme Fe(II)/ Fe(III) of the well-oriented Mb in Brij 56 matrix. The surface coverage and the electron transfer rate (ks) of Mb immobilized into the Brij 56 film was about 4.9×10-11 mol cm-2 and 72.6 3.0 s-1, respectively. An excellent electrocatalytic response of the immobilized Mb towards nitrite in the absence of electron transfer mediators was observed. These results emphasized that the biomimetic Brij 56 could be used as an attractive material for immobilizing proteins and constructing biosensors.
    ACS Applied Materials & Interfaces 05/2015; 7(21). DOI:10.1021/acsami.5b01492 · 6.72 Impact Factor
  • Yang Wang · Huali Ge · Guiqin Ye · Huanhuan Chen · Xiaoya Hu
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    ABSTRACT: Carbon functionalized metal organic frameworks (C/Al-MIL-53-(OH)2) were successfully prepared for the first time by a solvothermal technique and characterized by Fourier transform infrared spectroscopy, X-ray diffraction spectrometry, and scanning electron microscopy. This composite was coated with a Nafion film so as to form a Nafion/C/Al-MIL-53-(OH)2 modified glassy carbon electrode. The modified electrode was then used as a novel electrocatalyst for dopamine (DA) oxidation in phosphate buffer solution. Due to the synergistic effects of the different materials, including the high conductivity of carbon, the large surface area of Al-MIL-53-(OH)2, and the film-forming ability of a cation-exchange polymer, the modified electrode exhibited a remarkable enhancement effect on voltammetric response of DA. Under the optimal conditions, the response peak currents had a linear relationship with the DA concentration in the range from 3.0 × 10−8 to 1.0 × 10−5 mol L−1. The limits of detection and quantitation for DA were found to be 0.8 × 10−8 mol L−1 and 2.6 × 10−8 mol L−1, respectively. The analytical utilities of the proposed biosensor were achieved by analyzing the content of DA in biological fluids.
    04/2015; 3(18). DOI:10.1039/C4TB01869A
  • Airong Mao · Hongbo Li · Zhaosheng Cai · Xiaoya Hu
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    ABSTRACT: A glassy carbon electrode modified with nano TiO2 and multi-walled carbon nanotubes composites dispersed in a novel cationic surfactant was described for the determination of trace mercury(II) by linear anodic stripping voltammetry. Under optimal experimental conditions, the linear sweep anodic stripping peak current was linear with the concentration of Hg(II) in the range of 0.1 to 100 μmol L-1 with a detection limit of 0.025 μmol L-1. The sensitivity was found to be 3.7014 A/ mol L-1. The proposed electrode also showed a high selectivity for mercury in the presence of common potential interfering metal ions. Moreover, the proposed electrode revealed good reproducibility and stability. The proposed method was successfully applied for the determination of Hg(II) in river water and industrial wastewater samples.
    Journal of electroanalytical chemistry 04/2015; 751. DOI:10.1016/j.jelechem.2015.04.034 · 2.87 Impact Factor
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    ABSTRACT: The accurate measurement of nitrate in PM2.5 is essential for a complete understanding of the effects of aerosols on human health, the impact of aerosols on the radiative balance of the earth and the role of aerosols in visibility problems. In this paper, we present a novel, quick, easy, cheap and eco-friendly electroanalytical procedure for the determination of nitrate in PM2.5 samples using a carbon-fiber micro-disk electrode (CFMDE) coupled with square-wave voltammetry (SWV). Under optimal experimental conditions the nitrate SWV response increases linearly with nitrate concentration over a range of 0.003-2.0mmolL(-1), and the detection limit is 1.10μmolL(-1) (S/N=3). Nitrate contents in daily PM2.5 of Yangzhou in China were detected successfully by employing this novel method, and the results were compared well with those obtained by using ion chromatography. Then, we detected nitrate in two-hour PM2.5 filter samples via the standard addition method, and the concentrations were applied in an analysis of the daily change of nitrate contained in PM2.5 of Yangzhou. The research in this work indicates that the electrochemical method opens a new opportunity for fast, portable, and sensitive analysis of components in PM2.5. Copyright © 2015 Elsevier B.V. All rights reserved.
    Talanta 04/2015; 143. DOI:10.1016/j.talanta.2015.04.049 · 3.51 Impact Factor
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    ABSTRACT: In this work, we reported an efficient platinum nanoparticles functionalized nitrogen doped graphene (PtNPs@NG) nanocomposite for devising novel electrochemical glucose biosensor for the first time. The fabricated PtNPs@NG and biosensor were characterized using transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, static water contact angle, UV-vis spectroscopy, electrochemical impedance spectra and cyclic voltammetry, respectively. PtNPs@NG showed large surface area and excellent biocompatibility, and enhanced the direct electron transfer between enzyme molecules and electrode surface. The glucose oxidase (GOx) immobilized on PtNPs@NG nanocomposite retained its bioactivity, and exhibited a surface controlled, quasi-reversible and fast electron transfer process. The constructed glucose biosensor showed wide linear range from 0.005 to 1.1mM with high sensitivity of 20.31mAM(-1)cm(-2). The detection limit was calculated to be 0.002mM at signal-to-noise of 3, which showed 20-fold decrease in comparison with single NG-based electrochemical biosensor for glucose. The proposed glucose biosensor also demonstrated excellent selectivity, good reproducibility, acceptable stability, and could be successfully applied in the detection of glucose in serum samples at the applied potential of -0.33V. This research provided a promising biosensing platform for the development of excellent electrochemical biosensors. Copyright © 2015 Elsevier B.V. All rights reserved.
    Analytica chimica acta 02/2015; 871. DOI:10.1016/j.aca.2015.02.029 · 4.52 Impact Factor
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    ABSTRACT: An enzymatic procedure based on a catalase biosensor for the detection of forchlorfenuron (CPPU) has been reported in this work. Catalase was immobilized on boron nitride (BN) sheets dispersed in chitosan by adsorption. The immobilized catalase exhibited direct electron transfer character and excellent electrocatalytic activity towards H2O2 reduction. After introducing CPPU into the H2O2 containing phosphate buffer solution, the catalase-catalyzed H2O2 reduction current decreased. By measuring the current decrease, CPPU can be determined in the range of 0.5–10.0 µM with the detection limit of 0.07 μM. The non-competitive inhibition behavior of CPPU towards catalase was verified by the Lineweaver–Burk plots. Long stability character has been ascribed to this biosensor. Possible use of this biosensor in flow systems is illustrated. The proposed biosensor has been successfully applied to CPPU determination in fruits samples with satisfactory results.
    Biosensors & Bioelectronics 01/2015; 63:294–300. DOI:10.1016/j.bios.2014.07.055 · 6.45 Impact Factor
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    ABSTRACT: We have developed an impedimetric immunosensor for the determination of bovine interleukin-4, a cytokine involved in the immune response to certain parasites and the development of some bovine diseases. Monoclonal antibody against bovine interleukin-4 was immobilized on a glassy carbon electrode modified with reduced graphene oxide and chitosan. Transmission electron microscopy, static contact angle measurement, and electrochemical impedimetry are used to characterize the immunosensor. The nanocomposite possesses a high surface area that is well suited for the immobilization of antibody. The relative increase in impedance on exposure of the sensor to solutions containing bovine interleukin-4 is linearly proportional to its logarithmic concentration in the 0.1 to 50 ng mL−1 and the detection limit is 80 pg mL−1. The immunosensor is selective, well reproducible, and acceptably stable. It presents a useful tool for further studies on the role of this cytokine in the immunology and pathogenesis of bovine diseases. Graphical Abstract An electrochemical impedance immunosensor is for the first time developed for label-free detection of bovine interleukin-4 (bov-IL-4) by immobilizing bov-IL-4 monoclonal antibody at reduced graphene oxide (rGO)/chitosan nanocomposite modified electrode.
    Microchimica Acta 01/2015; 182(1-2). DOI:10.1007/s00604-014-1331-5 · 3.72 Impact Factor
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    ABSTRACT: Bovine interferon gamma (BoIFN-γ) released by T cells plays very important roles in early diagnosis of Mycobacterium tuberculosis (MTB) infections and control of bovine tuberculosis. In this work, a label-free electrochemical impedance immunosensor is for the first time developed for highly sensitive determination of BoIFN-γ. Cylinder-shaped TiO2 nanorods are synthesized by a facile hydrothermal method, and show high surface area and good hydrophicility. The immunosensor is fabricated by the immobilization of BoIFN-γ monoclonal antibody on the TiO2 nanorods modified glassy carbon electrode. The prepared TiO2 and immunosensor are characterized using transmission electron microscopy, scanning electron microscopy, X-ray diffraction, contact angle measurement, cyclic voltammetry, and electrochemical impedance spectra. The BoIFN-γ concentration is measured through the relative increase of impedance values in corresponding specific binding of BoIFN-γ antigen and BoIFN-γ antibody. The relative increased impedance values are proportional to the logarithmic value of BoIFN-γ concentrations in a wide range of 0.0001 to 0.1 ng/mL with a low detection limit of 0.1 pg/mL. The developed BoIFN-γ immunosensor shows a 249-fold decrease in detection limit in comparison with current enzyme-linked immunosorbent assay. This study provides a new, simple, and highly sensitive approach for very potential application in early diagnosis of MTB infections and control of bovine tuberculosis.
  • Dangqin Jin · Qin Xu · Liangyun Yu · Xiaoya Hu
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    ABSTRACT: We describe a sensitive photoelectrochemical (PEC) sensor for the determination of the herbicide clethodim. The PEC sensor was constructed by using amino-MIL-125/TiO2 (MIL stands for Materials from Institute Lavoisier), an amino-functionalized metal-organic framework (MOF) modified with TiO2. The amino-MIL-125/TiO2 was synthesized by a simple one-step solvothermal method and placed on a glassy carbon electrode where it displays photoelectrocatalytic activity. Scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) spectroscopy and X-ray diffractometry (XRD) were used to characterize the amino-MIL-125/TiO2. In the sensing process, amino-MIL-125/TiO2 is illuminated by visible light to produce electrons. These excited electrons are delivered to the glassy carbon electrode, leaving positively charged holes (h+) on the surface of the amino-MIL-125/TiO2. The holes react with H2O to generate hydroxy radicals (•OH). Clethodim rapidly attacks the hydroxy radicals and improves the efficiency of charge separation, this leading to an enhanced photocurrent. Under the optimal experimental conditions, this photoelectrochemical method enables clethodim to be quantified in the concentration range from 0.2 to 25 μmol L−1, with a detection limit (3 S/N) of 10 nmol L−1. The assay was applied to the determination of clethodim in soil samples, and results were in acceptable agreement with data obtained by liquid chromatography/mass spectrometry. Graphical Abstract An amino-functionalized metal-organic framework (MOF) modified with titanium dioxide was synthesized and used as a new platform for photoelectrochemical sensing of the herbicide clethodim.
    Microchimica Acta 01/2015; DOI:10.1007/s00604-015-1505-9 · 3.72 Impact Factor
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    ABSTRACT: Metal-organic frameworks composite materials have received tremendous attention because of their versatile structures and tunable porosity for various applications. Herein, amino-functionalized metal-organic frameworks (NH2-Cu3(BTC)2; BTC=benzene-1,3,5-tricarboxylate) was prepared and used as a novel electrode modifier for the determination of trace levels of lead. NH2-Cu3(BTC)2 shows quite a good capability for the efficient adsorption of lead from aqueous solutions. The parameters affecting the electrochemical process, such as electrolyte solution pH, the amount of NH2-Cu3(BTC)2 suspension, accumulation potential and accumulation time, were investigated in detail. Under the optimal conditions, the electrochemical sensor exhibited a linear response to the concentration of lead in the range of 1.0×10(-8)-5.0×10(-7)molL(-1) (R(2)=0.9951) with a detection limit of 5.0×10(-9)molL(-1). The relative standard deviation of 11 successive scans was 3.10% for 1.0×10(-8)molL(-1) lead. The method was validated with certified reference material (stream sediment and milk powder) and the analytical results coincided well with the certified values. Furthermore, the method was successfully applied to the determination of target analytes in tap and lake water samples and good recoveries were obtained from different spiked values.
    Talanta 11/2014; 129:100–105. DOI:10.1016/j.talanta.2014.05.014 · 3.51 Impact Factor
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    ABSTRACT: In this work, a novel chemically modified electrode is constructed based on metal-organic frameworks and β-cyclodextrin (Cu3(BTC)2/β-CD, BTC = benzene-1,3,5-tricarboxylate) composite material. The electrode was used for simultaneous determination of guanine and adenine in a sequential injection lab-on-valve format and exhibited sensitive responses to guanine and adenine oxidation due to the π-π stacking interaction of Cu3(BTC)2 and the inclusion behavior of β-CD. The analytical performance was assessed with respect to the supporting electrolyte and its pH, accumulation time and accumulation potential, and the fluid flow rates. Under optimal conditions, linear calibration ranges for both guanine and adenine were from 1.0 × 10(-7) to 1.0 × 10(-5) mol L(-1), and detection limits (S/N = 3) were found to be 5.2 × 10(-8) and 2.8 × 10(-8) mol L(-1), respectively. The proposed sensor showed advantages of high sensitivity, simple sample preparation protocol, enhanced throughput and good reproducibility. Finally, the practical application of the proposed sensor has been performed for the determination of guanine and adenine in real samples with satisfactory results.
    The Analyst 10/2014; 139(23). DOI:10.1039/c4an00901k · 4.11 Impact Factor
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    ABSTRACT: NH2-MIL-125(Ti), as a highly porous titanium-based MOF, has been firstly reported to show an efficient photooxidation activity toward Mn2+ in pH 8.5 NH3-NH4Cl (0.04 M) buffer under visible light. Mn2+ was detected quantitatively by cathodic stripping voltammetric method based on the oxidized manganese product. The stripping peak currents on NH2-MIL-1 25(Ti)/CPE was linearly proportional to the concentration of Mn2+ in the range from 1.0 x 10(-8) to 1.0 x 10(-5) M with the detection limit of 4.0 10-9 M. This method has been successfully applied for the detection of Mn2+ in tea samples, and the results were in close agreements with those obtained by atomic absorption spectroscopic method.
    Sensors and Actuators B Chemical 10/2014; 201:274–280. DOI:10.1016/j.snb.2014.05.017 · 4.29 Impact Factor