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Anthony Turner - One of the best experts on this subject based on the ideXlab platform.

  • Ammonium Ion requirement and stability of methanol dehydrogenase TTF·TCNQ electrodes
    The Analyst, 1996
    Co-Authors: M. G. Loughran, Victor L. Davidson, Jennifer M. Hall, Anthony Turner
    Abstract:

    The Ammonium Ion requirement and stability of quinoprotein methanol dehydrogenases were investigated with a view to incorporating them in enzyme electrodes for alcohol. This involved consideratIon of the effect of temperature and polyelectrolytes on enzyme stability. A packed cavity electrode was constructed using the organic conducting salt TTF·TCNQ (tetrathiafulvalene–tetracyanoquinodimethane). Methanol dehydrogenase isolated from Paracoccus denitrificans was more stable than the enzyme isolated from Methylophilus methylotrophus and was successfully used for repeated assay in packed cavity electrodes without significant loss in current output. These investigatIons also showed that, contrary to suggestIons in the literature, Ammonium Ions are necessary for efficient re-oxidatIon of methanol dehydrogenase at the organic conducting salt electrode.

  • Ammonium Ion requirement and stability of methanol dehydrogenase ttf tcnq electrodes
    Analyst, 1996
    Co-Authors: M. G. Loughran, Victor L. Davidson, Jennifer M. Hall, Anthony Turner
    Abstract:

    The Ammonium Ion requirement and stability of quinoprotein methanol dehydrogenases were investigated with a view to incorporating them in enzyme electrodes for alcohol. This involved consideratIon of the effect of temperature and polyelectrolytes on enzyme stability. A packed cavity electrode was constructed using the organic conducting salt TTF·TCNQ (tetrathiafulvalene–tetracyanoquinodimethane). Methanol dehydrogenase isolated from Paracoccus denitrificans was more stable than the enzyme isolated from Methylophilus methylotrophus and was successfully used for repeated assay in packed cavity electrodes without significant loss in current output. These investigatIons also showed that, contrary to suggestIons in the literature, Ammonium Ions are necessary for efficient re-oxidatIon of methanol dehydrogenase at the organic conducting salt electrode.

Shuping Liang - One of the best experts on this subject based on the ideXlab platform.

  • AdsorptIon characteristics of Ammonium Ion by zeolite 13X.
    Journal of hazardous materials, 2008
    Co-Authors: Hong Zheng, Lijie Han, Yan Zheng, Hongmei Zhang, Donghong Liu, Shuping Liang
    Abstract:

    With synthetic wastewater, lab-scale batch experiments and column experiments were carried out to investigate the adsorptIon characteristics of Ammonium Ion by zeolite 13X which is a hydrothermally synthetic byproduct accompanied with preparatIon of potassium carbonate from insoluble potash ores. The Langmuir and Freundlich models were applied to describe the equilibrium isotherms for Ammonium Ion uptake and the Langmuir model agrees very well with experimental data. Thermodynamic parameters including changes in the standard free energy (DeltaG(0)), enthalpy (DeltaH(0)) and entropy (DeltaS(0)) were also calculated. The results show that the exchange process of Ammonium Ion by zeolite 13X is spontaneous and exothermic. The pseudo second-order kinetic model was found to provide excellent kinetic data fitting (R(2)>0.999). The effects of relevant dynamic parameters, such as influent flow rate, adsorbent bed height and initial Ammonium Ion concentratIon on the adsorptIon of Ammonium Ion were examined, respectively. The Thomas model was applied to predict the breakthrough curves and to determine the characteristic parameters of column useful for process design and was found suitable for describing the adsorptIon process of the dynamic behavior of the zeolite 13X column. The total adsorbed quantities, equilibrium uptakes and total removal percents of Ammonium Ion related to the effluent volumes were determined by evaluating the breakthrough curves obtained at different conditIons.

  • AdsorptIon characteristics of Ammonium Ion by zeolite 13X
    Journal of Hazardous Materials, 2008
    Co-Authors: Hong Zheng, Lijie Han, Yan Zheng, Hongmei Zhang, Donghong Liu, Shuping Liang
    Abstract:

    With synthetic wastewater, lab-scale batch experiments and column experiments were carried out to investigate the adsorptIon characteristics of Ammonium Ion by zeolite 13X which is a hydrothermally synthetic byproduct accompanied with preparatIon of potassium carbonate from insoluble potash ores. The Langmuir and Freundlich models were applied to describe the equilibrium isotherms for Ammonium Ion uptake and the Langmuir model agrees very well with experimental data. Thermodynamic parameters including changes in the standard free energy (ΔG0), enthalpy (ΔH0) and entropy (ΔS0) were also calculated. The results show that the exchange process of Ammonium Ion by zeolite 13X is spontaneous and exothermic. The pseudo second-order kinetic model was found to provide excellent kinetic data fitting (R2 > 0.999). The effects of relevant dynamic parameters, such as influent flow rate, adsorbent bed height and initial Ammonium Ion concentratIon on the adsorptIon of Ammonium Ion were examined, respectively. The Thomas model was applied to predict the breakthrough curves and to determine the characteristic parameters of column useful for process design and was found suitable for describing the adsorptIon process of the dynamic behavior of the zeolite 13X column. The total adsorbed quantities, equilibrium uptakes and total removal percents of Ammonium Ion related to the effluent volumes were determined by evaluating the breakthrough curves obtained at different conditIons. © 2008 Elsevier B.V. All rights reserved.

M. G. Loughran - One of the best experts on this subject based on the ideXlab platform.

  • Ammonium Ion requirement and stability of methanol dehydrogenase TTF·TCNQ electrodes
    The Analyst, 1996
    Co-Authors: M. G. Loughran, Victor L. Davidson, Jennifer M. Hall, Anthony Turner
    Abstract:

    The Ammonium Ion requirement and stability of quinoprotein methanol dehydrogenases were investigated with a view to incorporating them in enzyme electrodes for alcohol. This involved consideratIon of the effect of temperature and polyelectrolytes on enzyme stability. A packed cavity electrode was constructed using the organic conducting salt TTF·TCNQ (tetrathiafulvalene–tetracyanoquinodimethane). Methanol dehydrogenase isolated from Paracoccus denitrificans was more stable than the enzyme isolated from Methylophilus methylotrophus and was successfully used for repeated assay in packed cavity electrodes without significant loss in current output. These investigatIons also showed that, contrary to suggestIons in the literature, Ammonium Ions are necessary for efficient re-oxidatIon of methanol dehydrogenase at the organic conducting salt electrode.

  • Ammonium Ion requirement and stability of methanol dehydrogenase ttf tcnq electrodes
    Analyst, 1996
    Co-Authors: M. G. Loughran, Victor L. Davidson, Jennifer M. Hall, Anthony Turner
    Abstract:

    The Ammonium Ion requirement and stability of quinoprotein methanol dehydrogenases were investigated with a view to incorporating them in enzyme electrodes for alcohol. This involved consideratIon of the effect of temperature and polyelectrolytes on enzyme stability. A packed cavity electrode was constructed using the organic conducting salt TTF·TCNQ (tetrathiafulvalene–tetracyanoquinodimethane). Methanol dehydrogenase isolated from Paracoccus denitrificans was more stable than the enzyme isolated from Methylophilus methylotrophus and was successfully used for repeated assay in packed cavity electrodes without significant loss in current output. These investigatIons also showed that, contrary to suggestIons in the literature, Ammonium Ions are necessary for efficient re-oxidatIon of methanol dehydrogenase at the organic conducting salt electrode.

Yukitaka Yamamoto - One of the best experts on this subject based on the ideXlab platform.

  • Urea biosensor based on amperometric Ammonium Ion electrode
    Electroanalysis, 1993
    Co-Authors: Mitsugi Senda, Yukitaka Yamamoto
    Abstract:

    An amperometric urea biosensor is described: urease is immobilized on the amperometric Ammonium Ion electrode surface, and the Ammonium Ion produced by hydrolytic decompositIon of urea by urease is determined by the pulse amperometric technique. Theoretical consideratIons on the steady-state concentratIon distributIon of the substrate (urea) and the product (sum of ammonia and Ammonium Ion) in the immobilized-enzyme layer show that the concentratIon of the product at the Ion-selective electrode surface is proportIonal to the concentratIon of the substrate at the solutIon side surface of the immobilized-enzyme layer up to a certain limiting concentratIon. The limiting concentratIon depends on the enzyme-loading factor (Thiele modulus) as well as the Michaelis constant of the enzyme reactIon. A practical urea sensor was constructed by immobilizing urease on an amperometric ammonia gas sensor. Preliminary experimental results and discussIon are given. With the amperometric urea sensor, the correctIon for the residual Ammonium Ion in test solutIon can be easily achieved with an auxiliary, amperometric urease-removed urea sensor.

  • Amperometric Ammonium Ion sensor and its applicatIon to biosensors
    Sensors and Actuators B: Chemical, 1993
    Co-Authors: Yukitaka Yamamoto, Mitsugi Senda
    Abstract:

    Abstract A urea biosensor based on the amperometric determinatIon of ammonia produced by hydrolytic decompositIon of urea by urease is described. The urease is immobilized on the amperometric Ammonium Ion-selective electrode sensor. This urea sensor gives the current response proportIonal to the concentratIon of urea in the range of a few to 100 ΩM in test solutIons. The response can be corrected for the residual Ammonium Ions. The urea sensor was successfully applied to the analysis of biological fluids. An amperometric creatinine biosensor is also described.

Tomomi Ujihara - One of the best experts on this subject based on the ideXlab platform.

  • biting effect stabilizing gallate type catechin quaternary Ammonium Ion complexes
    Tetrahedron, 2007
    Co-Authors: Nobuyuki Hayashi, Tomomi Ujihara
    Abstract:

    Abstract The relatIonship between the structure of catechins and their binding ability for quaternary Ammonium Ions was examined. From binding studies using eight catechins and benzyltrimethylAmmonium chloride, it was revealed that the binding ability of the gallate-type catechins is much higher than that of the non-gallate-type catechins. The quaternary Ammonium Ion binding site of the gallate-type catechins was determined to be the space formed by the galloyl group and the B-ring. The excellent binding ability of the gallate-type catechins is attributed to the ‘biting effect’ by the galloyl group and the B-ring.

  • ‘Biting effect’ stabilizing gallate-type catechin/quaternary Ammonium Ion complexes
    Tetrahedron, 2007
    Co-Authors: Nobuyuki Hayashi, Tomomi Ujihara
    Abstract:

    Abstract The relatIonship between the structure of catechins and their binding ability for quaternary Ammonium Ions was examined. From binding studies using eight catechins and benzyltrimethylAmmonium chloride, it was revealed that the binding ability of the gallate-type catechins is much higher than that of the non-gallate-type catechins. The quaternary Ammonium Ion binding site of the gallate-type catechins was determined to be the space formed by the galloyl group and the B-ring. The excellent binding ability of the gallate-type catechins is attributed to the ‘biting effect’ by the galloyl group and the B-ring.