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Hevesy, György

lead radioactive water measure

[he veshee] (1885–1966) Hungarian–Swedish radiochemist: introduced use of radioactive ‘tracers’ in analysis.

Hevesy was a highly mobile chemist; he worked in at least nine research centres in seven countries. His visit to work with in Manchester (1911–13) established his interest in radiochemistry. While there he found that ordinary lead and radioactive ‘radium-D’ are chemically inseparable; later it was realized that radium-D is an isotope of lead, with relative atomic mass 210, that happens to be radioactive. Consequently, very small amounts of lead can be ‘traced’ by mixing into the lead some radium-D and then taking advantage of the fact that minute levels of radioactive material are easily located by using a counter, or by photography. In this way Hevesy and F A Paneth (1887–1958), in 1913, were able to find the solubility in water of lead sulphide and lead chromate; both are insufficiently soluble for traditional methods to measure their solubility accurately. In 1934 he used a stable but trackable isotope (deuterium) in heavy water, D2O, to measure the water exchange between goldfish and their surroundings. In 1934 also he used radiophosphorus to locate phosphate absorption in human tissue. The technique has since been much used and suitable ‘marker’ isotopes for use as tracers are now widely available. In 1935 he devised a variant of this, activation analysis.

In 1922 predicted the existence of a new element and suggested that Hevesy should look for it in zirconium ore. Working with D Coster (1889–1950), who had experience of X-ray method, Hevesy found the new element (atomic number 72) and it was named hafnium (Hf). He was awarded a Nobel Prize in 1943 for his work on tracers.

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