Curtin University Homepage
  • Library
  • Help
    • Admin

    espace - Curtin’s institutional repository

    JavaScript is disabled for your browser. Some features of this site may not work without it.
    View Item 
    • espace Home
    • espace
    • Curtin Research Publications
    • View Item
    • espace Home
    • espace
    • Curtin Research Publications
    • View Item

    Limitations of Current Polarization for Lowering the Detection Limit of Potentiometric Polymeric Membrane Sensors

    Access Status
    Fulltext not available
    Authors
    Hofler, L.
    Bedlechowicz, I.
    Vigassy, T.
    Gyursanyi, R.
    Bakker, Eric
    Pretsch, E.
    Date
    2009
    Type
    Journal Article
    
    Metadata
    Show full item record
    Citation
    Hofler, Lajos and Bedlechowicz, Iwona and Vigassy, Tamas and Gyursanyi, Robert E. and Bakker, Eric and Pretsch, Erno. 2009. Limitations of Current Polarization for Lowering the Detection Limit of Potentiometric Polymeric Membrane Sensors. Analytical Chemistry 81: pp. 3592-3599.
    Source Title
    Analytical Chemistry
    DOI
    10.1021/ac802588j
    ISSN
    00032700
    Faculty
    Nanochemistry Research Institute (NRI)
    Faculty of Science and Engineering
    School
    Nanochemistry Research Institute (Research Institute)
    URI
    http://hdl.handle.net/20.500.11937/25396
    Collection
    • Curtin Research Publications
    Abstract

    Ion fluxes across polymeric ion-selective membranes are a decisive parameter dictating the lower detection limit of potentiometric ion sensors. An applied current was earlier proposed to counteract such fluxes and reduce the detection limit to ultratrace levels. So far, however, the method has not been used in practical situations since the correct current amplitude requires prior knowledge of the sample composition. This paper explores the use of the stir effect to evaluate the optimal current by theory and experiments. It is shown that the traditionally used steady-state model assuming a uniform distribution of ion exchanger in the membrane, fixed with time, violates the electroneutrality condition. A modified steady-state model is introduced that allows for a concentration tilt of the ion exchanger and predicts that a stir effect can indeed be utilized to find the optimal current. Ideally, by choosingthe optimal current and very long measurement times, the thermodynamic detection limit might be obtained. However, in practice the stir effect declines at low concentrations and the conditions are far from steady state. Therefore, the improvement of the lower detection limit achievable by galvanostatic control is only about 1 order of magnitude. A numerical finite-difference approximation is shown to trace the experimental potential responses of silver-selective electrodes well and to reproduce the stireffect adequately, even for different conditioning protocols. The stir effect is successfully used to improve the detection limit of electrodes with ill-optimized inner solutions; however, significant improvements beyond what is commonly feasible by chemical optimization does not seem to be easily achievable. The results indicate that with conventional membranes the possibility of improving the detection limit by current polarization is much more limited than assumed so far.

    Related items

    Showing items related by title, author, creator and subject.

    • Pretreatment of wastewater containing fats and oils using an immobilized enzyme.
      Jia, Huanfei (2002)
      This thesis investigates an application of immobilized lipase for pre-treating wastewater containing fats and oils, which is difficult to treat practically. The kinetics of soluble lipase was studied for establishing ...
    • Size exclusion chromatography as a tool for natural organic matter characterisation in drinking water treatment
      Allpike, Bradley (2008)
      Natural organic matter (NOM), ubiquitous in natural water sources, is generated by biogeochemical processes in both the water body and in the surrounding watershed, as well as from the contribution of organic compounds ...
    • Characterisation of aquatic natural organic matter by micro-scale sealed vessel pyrolysis
      Berwick, Lyndon (2009)
      The analytical capacity of MSSV pyrolysis has been used to extend the structural characterisation of aquatic natural organic matter (NOM). NOM can contribute to various potable water issues and is present in high ...
    Advanced search

    Browse

    Communities & CollectionsIssue DateAuthorTitleSubjectDocument TypeThis CollectionIssue DateAuthorTitleSubjectDocument Type

    My Account

    Admin

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Follow Curtin

    • 
    • 
    • 
    • 
    • 

    CRICOS Provider Code: 00301JABN: 99 143 842 569TEQSA: PRV12158

    Copyright | Disclaimer | Privacy statement | Accessibility

    Curtin would like to pay respect to the Aboriginal and Torres Strait Islander members of our community by acknowledging the traditional owners of the land on which the Perth campus is located, the Whadjuk people of the Nyungar Nation; and on our Kalgoorlie campus, the Wongutha people of the North-Eastern Goldfields.