Jaroslav Heyrovský

Jaroslav Heyrovský ( born December 20, 1890, in Prague, † March 27, 1967 in Prague) was a Czech physical chemist. His most important contribution to science was the development of polarography. For this he received the 1959 Nobel Prize in Chemistry.

Life

Jaroslav Heyrovský was the son of a professor of law. At the University of Prague in 1909, he studied physics, mathematics and chemistry. Between 1910 and 1914 he continued his studies at University College London. In 1913, he obtained a Bachelor of Science degree at Sir William Ramsay. In the years following the First World War, he was drafted as a soldier in the Austro-Hungarian army. In the medical service he was employed as a chemist in radiology. Nevertheless, he continued his studies to obtain a PhD in 1918 in Prague. In 1920 he completed his habilitation at the University of Prague. Subsequently, he worked as a lecturer in Physical Chemistry. In London in 1921, he degree of Doctor of Science ( D.Sc. ) was awarded. At the University of Prague in 1922 Heyrovský associate professor and in 1926 Professor of Physical Chemistry. He was from 1950 director of the newly founded polarography Institute of Charles University, Prague. This institution later became the " Heyrovský Institute for polarography of the Academy of Sciences of the Czechoslovak Socialist Republic " about. The Institute carries his name. For outstanding achievements in the field of electrochemistry named after him Heyrovský Medal is awarded. Heyrovský was from 1956 a member of the German Academy of Sciences Leopoldina.

Work

Invention of polarography

In defending his doctoral thesis in 1918 Professor Kucera was present and woke Heyrovskýs interest for the dropping mercury electrode. This one used to investigate Elektrokapillarkräfte. These weighed the experimenter either the fallen drops of mercury, or he determined the dropping time. The values ​​you wore as a graph against each applied electrochemical potential. The end of 1921 Heyrovský came up with the idea of ​​measuring the electric current that flowed through the electrochemical cell and thus through the dropping mercury electrode. These experiments access only when a particularly delicate mirror galvanometer was used. Only these measurements were then able to measure the tiny electrolysis currents ( nA to uA ) at the dropping mercury electrode in dependence on the applied potential. From 1922 he took on such current - voltage curves by hand with its employees. It was found that the electrolysis of dissolved chemical substances, resulting in step-shaped signals. The height of the step was dependent on the concentration. You could, for example, still capture metal ions at trace levels ( 10 .. 100 micromol / L ) with it. The position of the stage on the potential axis, however, was characteristic of the reacting substance. This electrochemical analysis method of polarography using the dropping mercury electrode used in the following decades quickly throughout the world. It enables quantitative and qualitative analysis of substances that can be implemented at the mercury electrode.

Further development of the polarographic method

Heyrovský developed with his colleague Shikato from 1924 the electromechanical polarograph. This device could automatically record polarograms and thus facilitated the polarographic experiments crucial. For the next nearly 40 years dominated this electro-mechanical type of instrument. Then electronic potentiostat were in use, which have been coupled with the dropping mercury electrode. Nowadays, a modern Polarograph is completely computer controlled. From 1926 published Heyrovský first publications on the new method. In the following years he devoted himself to theoretical studies of diffusion-limited currents and mechanisms of electrode reactions. Furthermore, he developed the mercury jet electrode and the alternating current polarography. In the latter, the smooth -varying voltage is still superimposed on an AC voltage, wherein the AC component is measured as an analytical signal.

Jaroslav Heyrovský has also contributed through books to spread his method. These easily understood works are devoted to both the theoretical foundations and the practical handling to concrete analysis rules.

Publications

• J. A. V. Butler; P. Zuman: Jaroslav Heyrovský. From 1890 to 1967. In: Biographical Memoirs of Fellows of the Royal Society. 13, 1967, pp. 167-191. doi: 10.1098/rsbm.1967.0008.

• LR Sherman: Jaroslav Heyrovský (1890 - 1967). In: Chemistry in Britain. December 1990, pp. 1165-1167.

• F. Calascibetta: Chemistry in Czechoslovakia in between 1919 and 1939: J. Heyrovský and the polarographic Prague School. In: Centaurus. 39, No. 4, 1997, pp. 368-381. doi: 10.1111/j.1600-0498.1997.tb00043.x.
• P. Zuman: Electrolysis with a Dropping Mercury Electrode: J. Heyrovsky 's Contribution to Electrochemistry. In: Critical Reviews in Analytical Chemistry. 31, No. 4, 2001, pp. 281 - 289 doi: 10.1080/20014091076767.
• J. Barek, AG Fogg, A. Muck, J. Zima: Polarography and Voltammetry at Mercury Electrodes. In: Critical Reviews in Analytical Chemistry. 31, No. 4, 2001, pp. 291-309. doi: 10.1080/20014091076776.
• Jiří Barek, Jiří Zima: Eighty Years of Polarography - History and Future. In: Electroanalysis. 15, No. 5-6, 2003, pp. 467-472. doi: 10.1002/elan.200390055.