J. Heyrovský, Japan, and organic polarography.

Polarography is an electroanalytical technique based on recording current-voltage curves using a dropping mercury as the working electrode. It can be used for investigations of both reductions and oxidations of inorganic and organic species. Before WWII the developments of this technique linked Prague (in the then Czechoslovakia) with Kyoto (in Japan, where reductions of organic compounds were first observed).

Nucleophilic attack by bromide ions as a first step of conversion of Se(VI) to Se(IV).

Numerous commonly used analytical methods allow only determination of a total amount of selenium in a given sample. Electroanalytical methods as well as those based on hydride generation or on formation of piazselenol allow only determination of Se(IV). To determine Se(VI) by these procedures, present alone or in mixtures with Se(IV), it is first necessary to convert Se(VI) to Se(IV).

Polarographic and voltammetric behavior of selenious acid and its use in analysis.

Solution chemistry of Se(IV), in particular the acid-base properties, salt and complex formation, chemical reduction and reaction of Se(IV) with organic and inorganic sulfur compounds are briefly summarized. The electrochemical reduction of Se(IV) on dropping and stationary mercury electrodes is dealt with in some detail. The effects of antecedent acid-base equilibria and of consecutive reactions of the reduction product, Se(2-), adsorption of their products, and effects of added metal ions are discussed.

Reactions of orthophthalaldehyde with ammonia and 2-aminoethanol.

Reactions of orthophthalaldehyde (OPA) with amines are used in the determination of amino acids and in applications of OPA as a biocide. To contribute to the understanding of processes involved, the reactions of OPA with ammonia, which are conveniently slow, were studied. In a set of rapidly established equilibria, the 1,3-dihydroxyindole and the product of its dehydration are formed (Scheme 1).

Electrochemical determination of HIV drug Abacavir based on its reduction.

Abacavir (I), a drug used in the treatment of HIV, is electrochemically reduced at the dropping mercury electrode in a four-electron process, similar to structurally related adenine (III) and adenosine triphosphate (IV). To undergo the reduction, the species is protonated in the vicinity of the electrode. The protonations take place on the 6-amino group and on one of the pyrimidine ring nitrogens.