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Journal ArticleDOI

Theory of Stationary Electrode Polarography. Single Scan and Cyclic Methods Applied to Reversible, Irreversible, and Kinetic Systems.

01 Apr 1964-Analytical Chemistry (American Chemical Society)-Vol. 36, Iss: 4, pp 706-723
TL;DR: In this paper, the integral equations obtained from the boundary value problems were solved and extensive data were calculated which permit construction of stationary electrode polarograms from theory, making it possible to develop diagnostic criteria so that unknown systems can be characterized by studying the variation of peak current, half-peak potential, or ratio of anodic to cathodic peak currents as a function of rate of voltage scan.
Abstract: was developed for solving the integral equations obtained from the boundary value problems, and extensive data were calculated which permit construction of stationary electrode polarograms from theory. Correlations of kinetic and experimental parameters made it possible to develop diagnostic criteria so that unknown systems can be characterized by studying the variation of peak current, half-peak potential, or ratio of anodic to cathodic peak currents as a function of rate of voltage scan.
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Journal ArticleDOI
TL;DR: Type III adenosine deaminase would be the best choice for the construction of an immobilized enzyme electrode both from the point of view of apparent Km and Vmax values and from the less pronounced product inhibition effect on the type III enzyme compared to the Type V enzyme.
Abstract: for each type of enzyme but in an opposite direction for each. The type III enzyme experiences an increase in apparent Km with increasing inosine concentration, while the type V enzyme shows a slight decrease in apparent Km at high inosine concentration. The most dramatic homogeneous effect is that of increasing inosine concentration upon the VmM values, however. For the type III enzyme, apparent VmiU! is reduced by nearly a factor of 2 but, for the type V enzyme, apparent Vma, decreases more than 7-fold. Such product inhibition reveals itself through longer response times in the immobilized enzyme electrodes. The results obtained in this study show that the potentiometric ammonia gas-sensing enzyme electrode does exhibit linear responses to substrate concentrations both above and below the Km value of the adenosine deaminase enzyme when sufficient enzyme is immobilized at the electrode surface. The BSA-glutaraldehyde cross-link provides for stabilization of the enzyme activity as shown by the observed electrode lifetime. Comparison of the homogeneous kinetic parameters with those obtained from the immobilized study reveals significant changes in the kinetic properties of the enzyme when it is immobilized, possibly resulting from conformational changes in the enzyme upon exposure to BSA and glutaraldehyde. The magnitude of the effect of addition of inosine on apparent Km and Vmax depends upon whether the enzyme is immobilized or free in solution. The apparent Km for the immobilized enzyme remained essentially constant upon addition of inosine, while the apparent Km for the homogeneous enzyme did show some variation but in opposite direction for the type III and V enzymes. In the construction of enzyme electrodes, it is desirable to obtain the highest (fastest rate) and lowest Km (greatest affinity) values possible. From the results of this study carried out at high enzyme levels it is apparent that type III adenosine deaminase would be the best choice for the construction of an immobilized enzyme electrode both from the point of view of apparent Km and Vmax values and from the less pronounced product inhibition effect on the type III enzyme compared to the Type V enzyme. Even in the absence of initial inosine, type III enzyme electrodes have faster response times than corresponding electrodes prepared with type V enzyme.

1,687 citations

Journal ArticleDOI
TL;DR: In this paper, a fundamental study of the influence of solvents on the oxygen reduction reaction (ORR) in nonaqueous electrolytes has been carried out for elucidating the mechanism of the oxygen electrode processes in the rechargeable Li−air battery.
Abstract: A fundamental study of the influence of solvents on the oxygen reduction reaction (ORR) in nonaqueous electrolytes has been carried out for elucidating the mechanism of the oxygen electrode processes in the rechargeable Li−air battery. Using either tetrabutylammonium hexafluorophosphate (TBAPF6) or lithium hexafluorophosphate (LiPF6) electrolyte solutions in four different solvents, namely, dimethyl sulfoxide (DMSO), acetonitrile (MeCN), dimethoxyethane (DME), and tetraethylene glycol dimethyl ether (TEGDME), possessing a range of donor numbers (DN), we have determined that the solvent and the supporting electrolyte cations in the solution act in concert to influence the nature of reduction products and their rechargeability. In solutions containing TBA+, O2 reduction is a highly reversible one-electron process involving the O2/O2− couple. On the other hand, in Li+-containing electrolytes relevant to the Li−air battery, O2 reduction proceeds in a stepwise fashion to form O2−, O22−, and O2− as products. Th...

876 citations

Journal ArticleDOI
TL;DR: This review provides a comprehensive overview of novel battery systems and discusses the numerous classes of organic, polymer-based active materials as well as auxiliary components of the battery, like additives or electrolytes.
Abstract: The storage of electric energy is of ever growing importance for our modern, technology-based society, and novel battery systems are in the focus of research. The substitution of conventional metals as redox-active material by organic materials offers a promising alternative for the next generation of rechargeable batteries since these organic batteries are excelling in charging speed and cycling stability. This review provides a comprehensive overview of these systems and discusses the numerous classes of organic, polymer-based active materials as well as auxiliary components of the battery, like additives or electrolytes. Moreover, a definition of important cell characteristics and an introduction to selected characterization techniques is provided, completed by the discussion of potential socio-economic impacts.

825 citations

Journal ArticleDOI
TL;DR: Ruthenium Complexes as a Source of Inspiration, Reduction of Carbon Dioxide, and Concluding Remarks.
Abstract: 6.2. Photosystem II as a Source of Inspiration 2364 6.3. Ruthenium Complexes 2364 6.4. Manganese Complexes 2365 6.5. Concluding Remarks 2366 7. Reduction of Carbon Dioxide 2366 7.

769 citations

References
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Book
01 Jan 1957

2,700 citations

Book
01 Jan 1959
TL;DR: Treatise on analytical chemistry, Treatise of analytical chemistry as mentioned in this paper, treatise on analyzing analytical chemistry, TCA, and analytical chemistry literature, کتابخانه دیجیتالی دانشگاه علوم پزش
Abstract: Treatise on analytical chemistry , Treatise on analytical chemistry , کتابخانه دیجیتالی دانشگاه علوم پزشکی و خدمات درمانی شهید بهشتی

1,092 citations