Each October, the Nobel Prizes celebrate remarkable scientific achievements, some of which have their origins in unconventional places. In the case of George de Hevesy, who received the Nobel Prize in Chemistry in 1943 for his groundbreaking work on radioactive tracers, that unconventional place was a boarding house cafeteria in Manchester, U.K., in 1911.
De Hevesy’s Cafeteria Experiment
George de Hevesy had a hunch that the boarding house cafeteria staff was reusing leftovers from previous meals, as the daily soup seemed to contain the same ingredients as the day before. To test his theory, he used a small amount of radioactive material in his leftover meat. A few days later, armed with an electroscope, he measured the radioactivity in the prepared food. When he showed the results to his landlady, who was unwittingly serving recycled food, she exclaimed, “this is magic.” In reality, it was the inception of the first successful radioactive tracer experiment.
Revolutionizing Science with Radioactive Tracers
Fast forward to today, where we, a team of chemists and physicists at the Facility for Rare Isotope Beams, Michigan State University, continue to build upon de Hevesy’s early research. His work has revolutionized the way modern scientists use radioactive materials, leading to numerous scientific and medical advances.
The Nuisance of Lead
A year prior to his cafeteria experiment, George de Hevesy had traveled to the U.K. to collaborate with nuclear scientist Ernest Rutherford, who had won a Nobel Prize just two years earlier. Rutherford was working with radium D, a radioactive substance with a long half-life. However, he couldn’t use it because it was contaminated with lead. De Hevesy was tasked with the challenging job of separating radium D from the troublesome lead.
De Hevesy spent nearly two years attempting to separate radium D from natural lead using chemical techniques, but he was unsuccessful. Little did anyone know that radium D was, in fact, a radioactive isotope of lead, Pb-210. This failure, however, led to a significant discovery: the use of radium D as a tracer for lead.
The Power of Radioactive Tracers
Radioactive isotopes, like Pb-210, are unstable and undergo radioactive decay over time, emitting detectable particles or light. This property makes them excellent tracers, as they stand out in a crowd of similar materials due to their unique radioactivity. De Hevesy’s ingenious idea was to track the movement of radium D (the “smartwatch”) among lead atoms (the “kindergartners”) by monitoring emitted radioactivity (the “GPS signal”).
Expanding Research in Vienna
In 1912, de Hevesy continued his experiments in Vienna, where the Vienna Institute of Radium Research had an extensive collection of radium and its byproducts. Teaming up with Fritz Paneth, another scientist who had struggled to separate radium D from lead, they introduced small amounts of radioactive tracers into various chemical compounds. This method allowed them to study chemical processes by tracking radioactivity through different reactions.
De Hevesy’s Legacy
George de Hevesy’s pioneering work on isotopic tracers earned him the 1943 Nobel Prize in Chemistry. Over a century later, radioactive tracers have become invaluable in various fields, from medicine to materials science and biology. They enable the monitoring of disease progression, nutrient uptake in plants, water flow and age in aquifers, and wear and corrosion of materials, among other applications.
Continuing the Legacy
Modern researchers focus on creating new isotopes and developing more efficient procedures for using radioactive tracers. At the Facility for Rare Isotope Beams (FRIB), unique radioisotopes are produced and employed in various applications, including medicine. Recent efforts at FRIB included the isolation of Zn-62 from irradiated water, a challenging task due to the vast difference in the number of water molecules and Zn-62 atoms. Zn-62 is a crucial radioactive tracer used to study zinc metabolism in plants and nuclear medicine.
George de Hevesy’s pioneering experiments, born from an everyday cafeteria observation, have profoundly impacted science and continue to inspire innovation in the field of radioactive tracers.
By Impact Lab