Potassium ion-selective electrode based on a cobalt(II)-hexacyanoferrate film-modified electrode |
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Authors: | Gao Zhiqiang Zhou Xingyao Wang Guangqing Li Peibiao Zhao Zaofan |
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Affiliation: | Department of Chemistry, Wuhan University, Wuhan, Hubei 430072 China |
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Abstract: | A potassium ion-selective electrode based on a cobalt(II)-hexacyanoferrate(III) (CHCF) film-modified glassy carbon electrode is proposed. The electroactive film is introduced onto the glassy carbon electrode surface by electrodeposition of cobalt, which forms a thin CHCF film on subsequent anodic scanning in KClHCl solution (pH 5.0–5.5) containing K3Fe(CN)6. The thickness of the film on the electrode surface can be controlled by changing the electrodeposition time and the concentrations of cobalt(II) and Fe(CN)3?6 ions. The modified electrode exhibits a linear response in the concentration range 1 × 10?1 ?3 × 10?5 M potassium ion activity, with a near-Nernstian slope (48–54 mV per decade) at 25 ± 1°C. The detection limit is 1 × 10?5 M. The stability, response time and selectivity were investigated. The electrode exhibits good selectivity for potassium ion with the twelve cations investigated. The relative standard deviation is 1.5% (n=10). The effects of the thickness of the electroactive film and the pH of the solution on the electrode response were also investigated. |
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Keywords: | Potentiometry Ion-selective electrodes Potassium |
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