Interest in polarography

They were soon joined by some of his older pupils. In this way one of his ambitions became fulfilled - to see his co-workers, whom he taught and interested in polarography, able to carry on research in this and related fields of electrochemistry. The group, nevertheless, suffered some losses - of R. Brdicka who first stayed at Charles University, but in 1952 became the Director of the Institute of Physical Chemistry, of J. Koutecky who turned his interest to quantum chemistry and of V. Hanus and V. Cermak who started a new career in mass spectrometry. 

Because of these advantages, polarography became very popular immediately after its inception in 1922. For the development of this method, Heyrovsky was awarded a Nobel prize in 1959. Over the period from 1922 to 1960, several tens of thousands of papers concerned with the use and improvement of polarography were published. However, interest in this method declined markedly in the 1960s, due primarily to a drastic increase in the requirements to be met by methods of chemical analysis. With the production of new superpure materials and increasing awareness for ecological problems, it became necessary to develop much more sensitive methods of analysis able to detect the different impurities down to a level of 10 M. 

Equation (4.5) is also valid in this case. Reactions of this type are realized in polarography at a dropping mercury electrode, and the standard potentials can be obtained from the polarographic half-wave potentials ( 1/2)- Polarographic studies of metal ion solvation are dealt with in Section 8.2.1. Here, only the results obtained by Gritzner [3] are outlined. He was interested in the role of the HSAB concept in metal ion solvation (Section 2.2.2) and measured, in 22 different solvents, half-wave potentials for the reductions of alkali and alkaline earth metal ions, Tl+, Cu+, Ag+, Zn2+, Cd2, Cu2+ and Pb2+. He used the half-wave potential of the BCr+/BCr couple as a solvent-independent potential reference. As typical examples of the hard and soft acids, he chose K+ and Ag+, respectively, and plotted the half-wave potentials of metal ions against the half-wave potentials of K+ or against the potentials of the 0.01 M Ag+/Ag electrode. The results were as follows ... 

Cyclic voltammetric methods, or other related techniques such as differential pulse polarography and AC voltammetry,3 provided a convenient method for the estimation of equilibrium constants for disproportionation or its converse, comproportionation. In this respect, the experimentally measured quantity of interest in a cyclic voltammetric experiment is E>A, the potential mid-way between the cathodic and anodic peak potentials. For a one-electron process, E,A is related to the thermodynamic standard potential Ea by equation (4).13 In practice, ,/2 = E° is usually a good approximation. 

One well-established observation is that, under conditions where single-stranded polynucleotides give rise to a d.c. polarographic reduction wave, both native DNA and other double-helical natural and synthetic polynucleotides are inactive 22 23,46-47, 58,59,61) Tjjjs js rea(ji]y interpretable in that, in such helical structures, the adenine and cytosine residues are located in the interior of the helix, and hydrogen bonded in complementary base pairs (see below). Z-DNA, in which cytosine residues are at the surface of the helix, is of obvious interest in this regard, and the B - Z transition in the synthetic poly(dG dC) has been investigated with the aid of differential pulse polarography and UV spectroscopy 60). 

The reader will find a systematic treatment based on older literature in the book by Bfezina and Zuman [3] or in a shorter version (in German) in a review [187]. More recent reviews present later development in a brief form [188]. If one is interested in the problems of polarographic activity of organic compounds, in pru ticular in mechanisms, Perrin s review [198] should be consulted. More details about polarography of heterocyclics are to be found in a specialised review chapter [6]. A vast quantity of material about organic electrochemistry are contained in a recent book [188a]. 

In addition to other information that can be obtained from polarographic curves (of interest in detailed electrochemical studies) there are two quantities that are of importance in the application of polarography to the solution of problems of reaction kinetics. These are the limiting current (% ), corresponding to the increase in current resulting from the electrolytic process and the half-wave potential the potential at... 

Most of the reported analytical work on dc polarography has been done using aqueous solutions because in the past metallic cation analysis dominated the field. As interest in the analysis of organic materials has grown and with the continuing use of polarographic methods in organic mechanism studies, the use of non-aqueous solvents has increased. 

One of the most successful analytical disciplines developed in Czechoslovakia, viz., polarography, has been employed both at home and abroad with good success. Its application in biochemical and medical laboratories, however, has been undeservedly lagging behind. This monograph presents both the most important information published in the literature, and, above all, our own methods, findings, interpretations, and ideas that may serve all workers interested in the polarographic method. 

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