George de Hevesy, Chemistry, 1943

Our chemical elements can exist as different isotopes – with a smaller or larger number of neutrons in the atomic nucleus and accordingly, different mass numbers. An example is carbon-14 with eight neutrons instead of the six that exist in “normal” carbon-12. Certain isotopes are unstable and fall apart. George de Hevesy showed that these radioactive isotopes can be used to follow the reactions of chemical substances.

Isotopes of the same chemical element have identical chemical characteristics. Using radioactive isotopes of a chemical element, George de Hevesy showed that radiation made it possible to follow the atoms through a long series of reactions. This was something that could be achieved by no other methods of analysis. Among other things, he showed how isotopes of phosphorus quickly entered the blood and then spread to various parts of the body. Sensitive methods for measuring radioactivity made it possible to, after some time, even find small traces of isotopes in dental enamel.

George de Hevesy was a pioneer in using isotopes to trace reaction pathways both in inorganic and organic chemistry and medicine. When the chemical reactions in cells could be followed, dynamic exchange processes of the biological systems could be observed for the first time. Various methods based on isotopes are now among the routine tools in research.

Hungarian-born George de Hevesy was a physicist and chemist and spent a great deal of his time at different European universities. Besides his discoveries on isotopes, he discovered the element hafnium in 1923, named after Hafnia, which is the Latin name for Copenhagen. George de Hevesy settled in Stockholm in 1943 and was then active as a researcher at Stockholm University College.