Teaching pH Measurements with a Student-Assembled Combination Quinhydrone Electrode

Fritz Scholz , Tim Steinhardt , Heike Kahlert and Jens R. Pörksen
Institut für Chemie und Biochemie, Universität Greifswald, D-17489 Greifswald, Germany
Jürgen Behnert
GAT Gamma Analysentechnik GmbH, D-27576 Bremerhaven–Lehe, Germany
J. Chem. Educ., 2005, 82 (5), p 782
DOI: 10.1021/ed082p782
Publication Date (Web): May 1, 2005

Abstract

A combination pH electrode that can be assembled by the student is described. It consists of a glass holder and two sensors in the form of rubber stoppers that contain quinhydrone and graphite. The combination electrode is suitable to teach potentiometric measurements, pH measurements, and the interplay of acid–base and redox equilibria. The electrode meets highest safety standards and overcomes the troubles associated with the use of the conventional quinhydrone electrode. Compared with commercial combination glass electrodes, the combination quinhydrone electrode has the didactic advantage that the sensor and the reference electrodes are both visible and not preassembled.

Keywords (Audience):

First-Year Undergraduate / General

Keywords (Domain):

Analytical Chemistry

Keywords (Pedagogy):

Hands-On Learning / Manipulatives

Keywords (Subject):

Acids / Bases

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This article has been cited by 2 ACS Journal articles (2 most recent appear below).

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      Journal of Chemical Education2010 87 (11), 1262-1264

      Inexpensive electrodes for the measurement of pH have been constructed using the ionophore tribenzylamine for sensing H+ concentrations. Both traditional liquid-membrane electrodes and coated-wire electrodes have been constructed and studied, and both ...

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    Plastic Membrane Sensor from a Disposed Combined Glass Electrode. A Project for Graduate and Fourth-Year Undergraduate Students of Analytical Chemistry

    Hayat M. Marafie and Adel F. Shoukry , Laila A. Alshatti
    Journal of Chemical Education2007 84 (5), 793
    • Plastic Membrane Sensor from a Disposed Combined Glass Electrode. A Project for Graduate and Fourth-Year Undergraduate Students of Analytical Chemistry

      Hayat M. Marafie and Adel F. Shoukry , Laila A. Alshatti
      Journal of Chemical Education2007 84 (5), 793

      A combined plastic membrane hydralazinium (Hz) selective electrode was constructed from a disposed combined glass electrode. The glass bulb was removed and a plastic membrane containing Hz–reineckate ion pair, as exchanger, was glued to a polyethylene cap ...

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History

  • Received: August 03, 2009

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