科研之友
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摘要
The glass electrode is the most commonly used device to access the pH of an aqueous solution. It attains highly accurate measurements via simple and well-established procedures. However, the reasons why the glass electrode potential scales with hydrogen ion concentration according to almost Nernstian potential values have been long-standing challenges to explain. Only in the past 50 years has an understanding of-the glass electrode response to pH been achieved, as elucidated by Nikolsky and Baucke and other researchers. In essence, the potential of a glass electrode derives from a solid-liquid electrolyte ionic process that entails both hydrated glass surface groups and diverse ions in solution. Thus, a process that is deceptively complicated-and usually overlooked underpins a boundary potential difference. This notwithstanding, other interpretations of the glass electrode response have been contributed. Most notably, Cheng has viewed the device 8 an electrical circuit condenser responding to adsorbed hydrogen or hydroxyl ions. In addition, Morrison has attributed the glass electrode response to a double layer surface-liquid interface potential. The purpose of this article is to portray an unusual mix of complexity and viewpoint disparity over the years. Knowledge and appreciation of this mix offer a more complete picture for students and educators of aqueous solution chemistry. This information is most appropriate to lecture and laboratory courses on quantitative analysis.
- 出版日期2013-3
