Samuel Ruben and Martin Kamen did just that and ..
Samuel Ruben and Martin Kamen (1941)
In 1941 SamuelRuben and Martin Kamen two prominent scientists “use isotopes to determine thatoxygen liberated in photosynthesis comes from the water” (Miller 205).
Samuel Ruben and Martin Kamen's experiment
A pair of men working at the University of California at Berkeley made a startling discovery on February 27, 1940 — one with implications for the future of science in everything from biology to anthropology. The two chemists, Martin Kamen and Samuel Ruben, realized basic the basic element of carbon had a radioactive isotope. Known as “carbon-14” due to its two additional neutrons, the ion exists in all sorts of natural organisms and can be used to estimate the age of materials up to 50,000 years old.