The Right Chemistry: 'Dirty bombs' and Prussian Blue
Fear of bombs with added radioactive material gave rise to a search for antidotes.
Article content
I think Goldfinger is the best of the James Bond movies. Remember the scene when Bond is secured to a table made of pure gold and Goldfinger activates a laser that starts to melt the metal and threatens to bisect 007? “Do you expect me to talk?” Bond asks. “No, Mr. Bond, I expect you to die!” Of course, Bond manages to escape and goes on to foil Goldfinger’s scheme of exploding a “dirty bomb” in Fort Knox to render the U.S. gold supply radioactive and unusable thereby increasing the value of his own stock of gold.
That was in 1964, before global terrorism introduced the possibility of using the combination of radioactive material and conventional explosives to inflict radioactive damage on a population.
A so-called “dirty bomb of course, requires the acquisition of radioactive material, which is not easy, but possible. There are a number of radioactive isotopes that are produced in nuclear reactors that have practical application. Cobalt-60 is used in the radiotherapy of cancer, americium-241 is used in smoke detectors and iridium-192 is used in industrial radiography to locate flaws in metal components. Terrorists could conceivably get their hands on such radioactive isotopes.
Much research has been dedicated to finding antidotes for radioactive materials that may be inhaled or ingested in case of a nuclear accident or terrorist attack. The most publicized has been the swallowing of potassium iodide pills with the intent of saturating the thyroid gland with iodide and preventing the uptake of radioactive iodide that may be released in a Chernobyl-type accident. Another possibility that has emerged is a pigment known as Prussian Blue, available under the name “Radiogardase.” Encased in gelatin capsules, the blue powder would be swallowed in case of radioactive substance exposure. Prussian Blue has the ability to bind the radioactive metal ions that are released by dirty bombs and subsequently eliminate them from the body. It can also be used in cases of thallium poisoning.
This pigment has a fascinating history. The name may ring a bell for people who remember Prussian Blue as one of the original Crayola colours. The name was changed to “midnight blue” in 1958, supposedly because the company thought people were mystified by the term “Prussian.” In any case, Prussian Blue was actually the first synthetic pigment ever discovered, predating mauveine, the first synthetic dye. Dyes are coloured soluble chemicals that are absorbed into the material to which they are applied, while pigments consist of extremely finely ground insoluble particles that coat a surface over which they are spread. Like Perkin’s famous accidental discovery of mauveine, the discovery of Prussian Blue was also serendipitous.
In 1706, Johann Jacob Diesbach, a colour merchant, needed help in producing a red dye from cochineal insects and consulted the philosopher and theologian Johann Konrad Dippel, who had a history of dabbling in alchemy. Dipple sought not only to turn base metals into gold, he also searched for the “elixir of life,” a potion that would enhance longevity. This, he believed, could be extracted from animal parts, particularly bones, after these had been decomposed by the addition of potash. Distillation of the mixture yielded a foul-tasting, malodorous oil that came to be known as “Dipple’s Oil.” Anything that tasted and smelled so bad had to be good for you! Dippel’s fame spread, and his universal cure flourished for 100 years.
Herr Diesbach had some experience with making a red dye from the cochineal insect by cooking the little bugs up with “green vitriol” and potash. But now he was having trouble finding potash. The substance referred to as green vitriol was iron sulphate, while potash was the “ash” left behind when a mixture of wood residue and vegetable matter was boiled to dryness in a “pot.” It was mostly potassium carbonate. Dippel, of course, had plenty of potash. After all, it was a key ingredient in his magical remedy. But when Dippel’s potash was mixed with Diesbach’s vitriol, the results were absolutely startling. A beautiful blue colour was formed! It turned out to be just the right hue for the uniforms of the Prussian army and came to be known as Prussian Blue. Artists also took to it. The sky in Vincent van Gogh’s famous Starry Night owes its stunning blue colour to Prussian Blue. The pigment quickly replaced the naturally occurring aquamarine, which was very expensive, given that it was derived from emeralds!
Neither Dipple nor Diesbach understood the chemistry of their accidental discovery. It seems the potash was contaminated with naturally occurring ferrocyanide that combined with iron sulphate in Diesbach’s cochineal solution to yield the novel blue. This chemistry was supposedly used by German spies during the Second World War to write secret messages. A solution of ferric sulphate can be used as invisible ink that turns blue when sprayed with ferrocyanide.
And there is one final twist to this story. Dippel supposedly also carried out dissections and experimented with transferring “souls” between cadavers with a funnel. In 1816, Mary Shelley, travelling with her husband Percy Bysshe Shelley along the Rhine, supposedly visited the castle where Dippel had carried out his anatomical experiments. The name of the castle? Castle Frankenstein. And the rest, as they say, is history.
Joe Schwarcz is director of McGill University’s Office for Science & Society (mcgill.ca/oss). He hosts The Dr. Joe Show on CJAD Radio 800 AM every Sunday from 3 to 4 p.m.
Postmedia is committed to maintaining a lively but civil forum for discussion. Please keep comments relevant and respectful. Comments may take up to an hour to appear on the site. You will receive an email if there is a reply to your comment, an update to a thread you follow or if a user you follow comments. Visit our Community Guidelines for more information.