著者
筒井 清二
出版者
The Polarographic Society of Japan
雑誌
Review of Polarography (ISSN:00346691)
巻号頁・発行日
vol.12, no.4, pp.103-112, 1964 (Released:2010-06-28)
参考文献数
8

There are three values in pH of nonaqueous or partialy aqueous solutions, that is to say, (1) the scale of proton activity in each solvent, (2) the scale of proton activity referred to the water scale, and (3) conventional pH. The value of (1) can be measured by using nonaqueous standard solution of the same solvent and it can not refer to that in another solvents. The value of (2) can only be measured in special solutions in which liquid junction potentials between the reference KCl solution are known and the value of (3) is usually measured in practical use. The e.m.f. of the glass electrode behaves in the same manner as the hydrogen elec-trode in nonaqueous solutions. But the asymmretry potential is far different from that in aqueous solutions. To stabilize the liquid junction potential, conventional pH of nonaqueous solutions must be measured by using the special means different from the aqueous solutions.
著者
木原 壯林
出版者
日本ポーラログラフ学会
雑誌
Review of Polarography (ISSN:00346691)
巻号頁・発行日
vol.60, no.1, pp.59-71, 2014-05-21 (Released:2014-05-28)
参考文献数
6
被引用文献数
1
著者
山本 雅博
出版者
日本ポーラログラフ学会
雑誌
Review of Polarography (ISSN:00346691)
巻号頁・発行日
vol.56, no.1, pp.11-30, 2010-05-31 (Released:2010-06-18)
参考文献数
11
被引用文献数
4 5

電気二重層は電極電位を決定するので電気化学において最も基本的な概念であり,スーパーキャパシター等の応用でも重要であるが,電気化学を専門としている学生諸氏の間で電気二重層の理屈はよくわからないとう声を良く聞く。帯電した電極を対(たい)イオンが遮蔽する静電相互作用 (Poisson方程式)とそのイオンが熱的に散らされて分布( Boltzmann分布)することを同時に考慮(非線形微分方程式)しなくてはならないからであろう。従って,電気2重層の理論は,電磁気学と (統計・ )熱力学に基礎を置く。化学系の学生は,電磁気学(より正確にはガウスの法則だけで十分だが)を理解しにくいてことが,よくわからない原因であるようだ。以下その点も考慮して解説した。付録に,ガウスの法則の説明を書いたので,電磁気学の復習も含めてそこから読んで欲しい。 ここでは, Gouyによって定式化された100年の歴史をもつ Gouy(-Chapman理論) [1, 2] 1および Stern[3]による補正をまず述べる。電気二重層の測定結果の解析においては,大抵の場合この GCS(Gouy-Chapman-Stern)理論で説明が(定性的にももちろん定量的にも)可能である。その後, Grahameが GCS理論に特異吸着の効果を入れてこの理論はある意味完成した [4]。この GCSG理論の基本方程式である非線形 Poisson-Boltzmann式を数値的に解くことにより,帯電界面をもつ3次元構造体(たとえばタンパク質)の電気二重層構造が明らかとなった。 その GCSG理論では,溶媒は無構造誘電体で,イオンの大きさ,イオン間の相互作用も考慮されてないので,電極が強く帯電している場合や電解質濃度が高い場合には一般には正しくない。紙面の都合で,その後進展してきた分子シミュレーションによる電気二重層の数値解については改めて述べたい。長距離力であるクーロン相互作用が帯電した界面で正確に考慮されてない分子シミュレーションの結果の取り扱いには慎重さを要することと,実験で得られている微分キャパシタンスの結果を再現したシミュレーションはまだないように思う。電解質水溶液の場合,溶媒分子数に比べて電解質のイオン数が少なく,シミュレーションで集団平均・時間平均をとることが困難であることも原因のひとつである。
著者
垣内 隆
出版者
日本ポーラログラフ学会
雑誌
Review of Polarography (ISSN:00346691)
巻号頁・発行日
vol.60, no.2, pp.99-109, 2014-09-24 (Released:2014-09-27)
参考文献数
22
被引用文献数
1 2

The criticism to the concept and use of single ion activity raised by de Levie (2010) has been examined. The lack of falsifiability in the concept of single ion activity, which he claims, led him to categorize the single ion activity as one of non-falsifiables, typified by the emperor’s new clothes (2012). However, his criticism is overeager, because the single ion activity can be estimated with a reasonable certainty, whose degree varies with a nonthermodynamic assumption employed, though. Electrochemistry is intrinsically nonthermodynamic, although in many of electrochemistry textbooks its cell voltage is correlated with the Gibbs energy of a redox reaction that would proceed in a homogeneous solution between the two redox couples, which are employed in the electrochemical cell. Ironically, such oversimplified understanding or picture of the nature of electrochemical cells partly justifies the criticism raised by de Levie. The obscurity associated with nonthermodynamic nature of electrochemical cells translates to the obscure interpretation of the Nernst equation in the form, E = E0 + (RT/F)ln(aOx/aRd), which has long been applied to a working electrode in electroanalytical chemistry. By focusing on this obscurity, it is possible not only to make our understanding of electroanalytical chemistry clearer but to design an electrochemical cell for less obscure, more reliable estimation of single ion activities.
著者
大堺 利行
出版者
日本ポーラログラフ学会
雑誌
Review of Polarography (ISSN:00346691)
巻号頁・発行日
vol.62, no.2+3, pp.109-114, 2016-10-17 (Released:2016-10-26)
参考文献数
9
被引用文献数
1

Laplace transform was first introduced to electrochemistry in 1947 by Koutecký and Brdička, who derived an analytical equation of the polarographic “kinetic current” for weak acids at the dropping mercury electrode. Since then, Laplace transform has been successfully used to solve diffusion problems in a variety of electrochemical measurement systems. This article shows how to apply Laplace transform to obtain an analytical equation of the current–potential curve for a simple redox system. A previous practical application made by the author has also been described.
著者
大堺 利行
出版者
日本ポーラログラフ学会
雑誌
Review of Polarography (ISSN:00346691)
巻号頁・発行日
vol.63, no.2, pp.101-107, 2017-10-10 (Released:2017-10-12)
参考文献数
13
被引用文献数
2 2

In 1935, Karl Fischer (KF) proposed a titration method for water content determination. Since then, KF titration has been extensively applied in the determination of water in various samples, including liquids, solids, and gases. The present article describes the reaction mechanism, the two different methods (i.e., volumetry and coulometry), and their instruments and advantages/disadvantages. As an example, an application of KF titration is described in the study of the coextraction of water with hydrophilic ions to water-immiscible organic solvents (e.g., nitrobenzene).
著者
尾関 徹 瀧川 勝三 谷田 高輝
出版者
日本ポーラログラフ学会
雑誌
Review of Polarography (ISSN:00346691)
巻号頁・発行日
vol.60, no.1, pp.49-58, 2014-05-21 (Released:2014-05-28)
参考文献数
9

Only letting water drop can generate electricity according to the idea of Load Kelvin, which has been known as Kelvin’s water droplet electric generator. Then what is the real carrier of electric charge in water droplets? We started this study from a curiosity on electrochemical understanding of aqueous solution. The study has led us the fact that this phenomenon is contradicting the well-known condition of analytical chemistry that an aqueous solution can be treated with the condition of electric neutrality anytime, although it is the problem of how much precisely we treat the condition of electric neutrality of aqueous solutions.
著者
福山 真央
出版者
日本ポーラログラフ学会
雑誌
Review of Polarography (ISSN:00346691)
巻号頁・発行日
vol.65, no.2, pp.63-64, 2019

<p>The aims of this technical note are to change the image the readers may have of "microfluidic device" and to invite the easy and inexpensive microfabrication using cutting machine.</p>
著者
片野 肇
出版者
The Polarographic Society of Japan
雑誌
Review of Polarography (ISSN:00346691)
巻号頁・発行日
vol.58, no.1, pp.13-22, 2012-05-31 (Released:2012-07-31)
参考文献数
5
被引用文献数
4 3

A simple potentiostat can be designed using three operational amplifiers. In this technical note, we will consider some basic circuits of operational amplifiers and the potentiostatic circuit. Controlling of the voltage in the potentiostatic system has been observed experimentally.
著者
今林 慎一郎
出版者
日本ポーラログラフ学会
雑誌
Review of Polarography (ISSN:00346691)
巻号頁・発行日
vol.54, no.2, pp.115-121, 2008 (Released:2008-11-07)
参考文献数
26
被引用文献数
9 13

Recent papers discussing the effect of surface roughness on wettability of solid surfaces are reviewed. Wenzel's and Cassie-Baxter's wetting models, factors determining the relative stability of the wetting models, and the control of the surface wettability by electrowetting are introduced.