b'The Right Chemistry: Natural Versus Synthetic ChemicalsTHERE ARE MANYconfrontations on theC-14, after some 5730 years, half the atoms will have battlefield of cyberspace. Vaccine proponentsdecayed. This is the basis of radiocarbon dating as well versus anti-vaxxers. Creationists versus evolutionaryas identifying a sample as being natural or synthetic.biologists. Anti-fluoride activists versus fluoridationWhen neutrons in cosmic rays emitted by stars supporters. Climate change deniers versus climateknock a proton out of nitrogen atoms in the atmos-scientists. However, one of the most vigorous debatesphere, they produce an atom of C-14. This C-14 then revolves around the relative merits of synthetic andreacts with oxygen to form carbon dioxide that is then natural chemicals.taken up by plants during photosynthesis and is used JOE SCHWARCZ The idea that natural substances have some sortin the biosynthesis of all the plants organic compo-Dr. Joe Schwarcz isof vital force that cannot be replicated in the labnents. Therefore, caffeine in a coffee bean will have Director of McGillwas dismissed as early as 1828 when Friedrich Wohlersome C-14. As long as a plant is alive, it keeps taking up Universitys Officesynthesized urea and showed it to be identical to thecarbon dioxide, so its C-14 content is the same as that for Science andnatural version isolated from urine. Nevertheless, theof the atmosphere. Once the plant dies, it no longer Society whichmyth that there is something magical about naturalphotosynthesizes, and its C-14 content will continue to has the mission ofsubstances persists to this day. Recently, I had andecrease through radioactive decay. By the time plant separating senseinquiry from an individual who was perturbed by matter becomes petroleum, its C-14 content will have from nonsense. learning that the caffeine in his energy drink originatedvirtually disappeared. in a lab and not in a coffee bean. I explained that a mol- Caffeine can be synthesized in the laboratory from ecule of caffeine is defined by its molecular structuresimple molecules that are sourced from petroleum, and and whether the atoms that make up that structure arethis version will have essentially no C-14. However,joined together by Mother Nature or by a chemistcaffeine from coffee beans will have some, and its makes no difference.presence can be detected either by measuring beta I thought I had provided a pretty convincing argu- ray emission or through mass spectrometry, an instru-ment. But then came a follow-up question. So, howmental technique that can detect small changes in come I saw this report about chemists finding that theatomic mass. caffeine in an energy drink didnt come from the coffeeCommercially, caffeine can be obtained either from bean but was synthetic? Good question. While it isthe decaffeination of coffee beans or through chemical true that in terms of molecular structure natural andsynthesis. In general, synthesis is cheaper, and most of synthetic caffeine are identical, there is a subtle differ- the caffeine that is added to energy drinks is produced ence in isotope ratios that allows for the identificationon a massive scale in China. Once produced, it is the of a sample as being natural or synthetic. same as any other caffeine. Well, almost. While the An element is defined by the number of protons indifference in C-14 content is only of academic interest, its nucleus. For example, every atom of carbon in thethere may be a difference in residues of processing universe has six protons in its nucleus. But the nucleuschemicals. In any chemical reaction the product will can also contain neutrons, particles that have the samecontain traces of the reagents used in its synthesis. weight as protons but have no effect on the identity ofThere have been questions raised about quality control the element. Atoms of the same element that differ inin some Chinese facilities. However, it is also possible the number of neutrons are called isotopes. Roughlythat in the case of caffeine obtained by decaffeinating 99% of all carbon atoms have six protons and six neu- coffee beans, traces of extraction solvents remain.trons and are referred to as carbon-12. A tiny, tiny frac- Basically though, when it comes to the consump-tion, one in a trillion carbon atoms, has eight neutrons.tion of caffeinated beverages, the question that should This isotope, carbon-14 (C-14), is radioactive, meaningbe asked is not whether the caffeine is natural or that one of its neutrons breaks down into a proton andsynthetic, but rather what impact the worlds most an electron. The emitted electrons constitute betawidely consumed psychoactive substance may have rays and can be detected. In any sample containingon health.SWDECEMBER 2020SEEDWORLD.COM /65'