• Disease
  • Enzyme
  • Enzyme Reactors
  • Werner E Morf

    Prominent publications by Werner E MORF

    KOL Index score: 6037

    On the basis of previously reported correlations between the lipophilicity of membrane components, their partition coefficient between the membrane and the sample, and the lifetime of corresponding neutral-carrier-based sensors, the lipophilicities of ionophores and plasticizers in analytically relevant ion-selective electrodes, ISFETs, and optodes are analyzed and reported. Equations for the estimation of the lifetimes of liquid membranes in continuous-flow systems are presented, and ...

    Also Ranks for: Membrane Components |  aqueous samples |  neutral carrier |  artificial animals |  selective electrodes
    KOL Index score: 4684

    A unified and comparative treatment of traditional potentiometric and amperometric enzyme electrodes and of enzyme reactors is presented. Exact theoretical descriptions are given for limiting cases, and relatively simple approaches for general cases. The latter approximations are obtained from the respective solutions for a two-segmented membrane model. They allow an explicit description and a full characterization of the response curves by only two kinetic parameters, which are the ...

    Also Ranks for: Enzyme Reactors |  concentration profiles |  theoretical treatment |  kinetic parameters |  response curves
    KOL Index score: 4637

    The fabrication and characterization of a combined pO2, pCO2 and pH chemical sensor, designed for blood-gas monitoring, are discussed. Classical electrochemical principles are used in a miniaturized planar-type structure. Both amperometric (pO2) and potentiometric devices (pCO2 pH) are integrated on a 10 mm × 10 mm chip. The transducer part of the chip is realized using standard silicon technology. Polyacrylamide and polysiloxane layers, which are used as hydrogel and gas-permeable ...

    Also Ranks for: Po2 Pco2 |  gas sensor |  polysiloxane layers |  permeable membrane |  planar type
    KOL Index score: 4626

    The time-dependent behavior of sensor systems based on enzyme membranes is treated theoretically. The comparative treatment covers traditional potentiometric and amperometric enzyme electrodes as well as enzyme reactors. Theoretical solutions are derived by the method of Laplace transforms. The relationships refer to the analytically useful range of relatively low substrate concentrations where the response signal is a function of the sample concentration. Numerical simulations using ...

    Also Ranks for: Enzyme Reactors |  numerical simulation |  theoretical treatment |  concentration profiles |  response time
    KOL Index score: 4367

    New mercury organic compounds with 1–3 metal centers and different substituants were synthesized as anion-selective ionophores. They were incorporated into solvent polymeric membranes, and the selectivity, slope of response, response time, emf repeatability, and the signal stability of the corresponding ion-selective electrodes (ISEs) were studied. Ortho-dimercury aromatic compounds were found to induce an adequate chloride-selectivity for physiological measurements. The anion ...

    Also Ranks for: Response Mechanism |  selective electrodes |  ises based |  chloride selectivity |  signal stability
    KOL Index score: 4005

    A theoretical approach to the steady-state limiting current response behavior of multiple microelectrode arrays, consisting of spherical, hemispherical, disk-shaped, or hemicylindrical electrode units, is presented. An approximative treatment is given for realistic arrays that contain microelectrodes of finite size and a rigorous description is offered for hypothetical arrays of point or line electrodes. The theories account for convection influences in the sample solution by restricting ...

    Also Ranks for: Theoretical Treatment |  microelectrode arrays |  current response |  electroactive species |  sample solution
    KOL Index score: 3644

    A novel electrochemiluminescence (ECL) detector is presented in this article. The detector is applied for micellar electrokinetic chromatographic separation of dichlorotris(2,2'-bipyridyl)ruthenium(II) hydrate [Ru-(bpy)] and dichlorotris(1,10-phenanthroline)ruthenium-(II) hydrate [Ru(phen)] on a microfabricated glass device. It consists of a microfabricated "U"-shape floating platinum electrode placed across the separation channel. The legs of the U function respectively as working and ...

    Also Ranks for: Separation Channel |  electric field |  ecl reaction |  amino acids |  micellar electrokinetic
    KOL Index score: 3537

    The sum of the concentrations of calcium and magnesium in water samples can be determined directly with a neutral carrier-based Mg2+/Ca2+-selective electrode (divalent ion-selective electrode), without addition of any auxiliary complexing agent such as acetylacetone. This approach works well, even in situations where calcium-selective electrodes do not detect the second inflection point because the calcium/magnesium concentration ratio is too high ([Ca2+]:[Mg2+] ⪢5:1) or the sodium ...

    Also Ranks for: Selective Electrode |  calcium magnesium |  water samples |  neutral carrier |  mg2 ca2
    KOL Index score: 3518

    Based on A theoretical treatment of neutral carrier liquid-membrane electrodes, propositions are derived to reduce the interference of the cation response by lipid-soluble anions in the sample solution. The performance of such electrodes is shown to be improved by incorporating lipophilic anions, such as tetraphenylborate, into the membrane. There is A quantitative agreement between the theoretical predictions and the results thus obtained for carrier based calcium- and ...

    Also Ranks for: Anion Interference |  neutral carrier |  theoretical predictions |  sample solution |  cation response
    KOL Index score: 3348

    Selectivities were measured for membrane electrodes containing a given amount of a neutral carrier (ETH 1692) and varying amounts of the additive potassium tetrakis(p-chlorophenyl)borate. The pronounced selectivity changes induced by the additive agreed with a theoretical model. Both theory and experiment confirmed that an optimum composition of the membrane exists. Ideally, sensors for monovalent cations should contain only small amounts of the additive, whereas sensors for divalent ...

    Also Ranks for: Optimum Composition |  membrane electrodes |  neutral carrier |  theoretical model |  divalent cations
    KOL Index score: 3333

    A new micro total analysis system (μTAS) designed for volumetric nanotitrations, integrating two electroosmotically driven nanopumps and a sensor unit, is presented. The unique feature of the integrated electroosmotic pumps is their ability to pump widely different solutions, independent of intrinsic characteristics such as pH or ionic strength, with the exception of viscosity. Typical flow rates achieved are in the range of 2–65nl/s, depending on the number of microchannels connected in ...

    Also Ranks for: Complex Capillary Systems |  partial electroosmotic pumping |  micro total analysis |  applied voltage |  fabrication application
    KOL Index score: 3331

    A thin aqueous layer is formed between the polymeric ion-selective membrane and an inner gold electrode. Its composition can be altered upon sample changes, which leads to drifting potentials. It is shown by theory and experiment that interfering ions enter the inner layer much faster than primary ones. Measurement protocols with equal contact times for the sample and the reconditioning solution can therefore not eliminate the effect of changes in the composition of the inner solution. ...

    Also Ranks for: Ion Fluxes |  potential drifts |  aqueous layer |  gold electrode |  measurement protocols
    KOL Index score: 3329

    Zero-current ion transport through polymeric membranes of ion-selective electrodes (ISEs) alters the composition of the inner solution of these sensors. This causes long-term drifts of the electromotive force that are relevant for miniaturized ISEs as well as for most solid-contacted ISEs in which a thin aqueous layer is formed between the membrane and the metal electrode during conditioning. By a similar mechanism, the composition of the sample can be significantly altered during the ...

    Also Ranks for: Response Behavior |  selective electrodes |  polymeric membrane |  composition solution |  aqueous layer
    KOL Index score: 3143

    Results of voltammetric, potentiometric, chronoamperometric, ion transport, and extraction studies on neutral carrier based, plasticized poly(vinyl chloride) membranes are summarized. They unambiguously confirm that such bulk membranes dispose of immobile anionic sites. These fixed sites lead to a Donnan exclusion of other anions from the membrane and thus to a permselectivity for cations. The results are in perfect agreement with the predictions of earlier membrane models. A rigorous ...

    Also Ranks for: Neutral Carrier |  polyvinyl chloride |  donnan exclusion |  fixed sites |  ion‐selective electrode


    Werner E MORF: Influence Statistics

    Sample of concepts for which Werner E MORF is among the top experts in the world.
    Concept World rank
    uniform electrodes response #1
    planar band electrodes #1
    sample solution theory #1
    complex formation redox #1
    rule array #1
    general treatment contributions #1
    coulometric nanotitrations #1
    coulometric nanotitrators applications #1
    nanotitrators #1
    variable average thickness #1
    membranebased reference systems #1
    origin transient response #1
    complex capillary systems #1
    coextracted ions #1
    microelectrodes multiple response #1
    reservoirs solutions #1
    anion‐selective #1
    electrode tips diameters #1
    electrodes theoretical #1
    calculation liquidjunction potentials #1
    titrations detection #1
    ionselective electrodes time #1
    meas cathodes #1
    threedimensional mixer #1
    microelectrode arrays concentration #1
    typical flow rates #1
    ideal multiple response #1
    microelectrode arrays idas #1
    membranebased reference devices #1
    10−3 analyte #1
    analyte linear #1
    transient response phenomena #1
    neutral ionophore eth #1
    limitations largescale miniaturization #1
    behavior conventional macroelectrode #1
    planar electrodes microchannel #1
    behavior liquidjunction contacts #1
    sensor unit fed #1
    membrane potentials basis #1
    macroelectrode total #1
    convection influences #1
    nanotitrators potentiometric #1
    single microelectrode contrast #1
    glass membrane electrodes #1
    nanotitrator #1
    solutions threedimensional mixer #1
    potentiometric response behavior #1

    Key People For Enzyme Reactors

    Top KOLs in the world
    Gillis Johansson
    flow injection enzyme reactor hydrogen peroxide
    Lo G O Gorton
    cellobiose dehydrogenase electron transfer hydrogen peroxide
    Howard H Weetall
    porous glass organic solvents immobilized enzyme
    Csaba G Horváth
    capillary electrochromatography liquid chromatography gradient elution
    Bo Olsson
    lung deposition flow rate enzyme reactors
    Lars Ögren
    enzyme reactor flow injection analysis immobilized urease

    Werner E MORF:Expert Impact

    Concepts for whichWerner E MORFhas direct influence:Enzyme reactors,  Neutral carriers,  Computer simulation,  Theoretical treatment,  Ion transport,  Neutral ionophores,  Enzyme electrodes,  Asymmetric membranes.

    Werner E MORF:KOL impact

    Concepts related to the work of other authors for whichfor which Werner E MORF has influence:Selective electrodes,  Neutral carrier,  Solid contact,  Response time,  Membrane electrode,  Concentration range,  Potentiometric titration.



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    École Polytechnique Fédérale de Lausanne (EPFL), Institute of Microengineering (IMT), Sensors, Actuators and Microsystems Laboratory (SAMLAB), P.O. Box 526, CH-2002 Neuchâtel, Switzerland | Institute of Microengineering (IMT), SAMLAB, Federal Institu