On the evening of the 29th February 1940, during the ceremony to award the Nobel Prize for Physics to Earnest Lawrence for his invention of the cyclotron, at the end of his address, Professor Birge made the surprise announcement of the discovery and isolation of carbon-14 to the assembled crowd that filled the hall.

"On the basis of its potential usefulness," Birge said, in a dramatic gesture, "this is certainly much the most important radioactive substance that has yet been created."

This was real news as the chemical isolation of carbon-14, in the form of its carbonate, had been achieved just 48 hours earlier by Martin Kamen and Sam Ruben.

Kamen, who was present at the ceremony, viewed C-14 as the most important single tool made available by tracer methodology and knew it would play an essential role in the elucidation of biochemical mechanisms.

Before the discovery of carbon-14 it had been predicted that the C-14 isotope would be radioactive, but on isolation it was found to be much longer–lived than expected with early estimates of the half-life being in the order of millennia. These proved to be correct when, several years later, the half-life of C-14 was determined at 5730 years.

Initially small quantities of C-14 were produced using a cyclotron. However, a decade later, through irradiation of nitride targets by thermal neutrons in a nuclear reactor, high specific activity C-14 became commercially available. Since then, synthetic chemists have become expert in incorporating C-14 atoms into molecules of interest, enabling C-14 radiotracer studies to be used routinely in medical and research work.

Today C-14 radiotracers continue to help broaden our understanding of the behaviour and fate of organic compounds in complex systems and their use is mandatory in key regulatory studies.

Selcia is proud to play a key role in producing bespoke C-14 radiotracers for these important studies.

As the largest independent supplier of high quality custom C-14 radiochemicals Selcia provides:

• C-14 custom radiolabelling - specialists in challenging syntheses & natural products

• GMP C-14 API for human ADME studies

• GLP CoA for environmental fate studies

For advice on radiolabelling, or a quotation, please contact us at contact@selcia.com