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A Solid-State Reference Electrode Based on a Self-Referencing Pulstrode |
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| Authors: | Dr Wenyue Gao Dr Elena Zdrachek Prof Xiaojiang Xie Prof Eric Bakker |
| Institution: | 1. Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva, Switzerland
Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055 China;2. Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva, Switzerland;3. Department of Chemistry, Southern University of Science and Technology, Shenzhen, 518055 China |
| Abstract: | The design of solid-state reference electrodes without a liquid junction is important to allow miniature and cost-effective electrochemical sensors. To address this, a pulse control is proposed using an Ag/AgI element as reliable solid-state reference electrode. It involves the local release of iodide by a cathodic current that is immediately followed by an electromotive force (EMF) measurement that serves as the reference potential. The recapture of iodide ions is achieved by potentiostatic control. This results in intermittent potential values that are reproducible to less than one millivolt (SD=0.27 mV, n=50). The ionic strength is shown to influence the activity coefficient of released iodide in accordance with the extended Debye–Hückel equation, resulting in a predictable change of the potential reading. The principle is applied to potentiometric potassium detection with a valinomycin-based ion-selective electrode (ISE), demonstrating a completely solid-state sensor configuration. |
| Keywords: | Elektrochemische Sensoren Elektrische Spannung Pulstrode Referenzelektrode Silberiodid |