A SOLUTION to SKUNK POLLUTION (From “Radar, Hula Hoops And, Playful Pigs” by Dr

A SOLUTION TO SKUNK POLLUTION (from “Radar, Hula Hoops and, Playful Pigs” by Dr. Joe Schwarcz, McGill University) I remember the first time I ever smelled a skunk. I thought someone had let off a stink bomb. You see, even back then I was a lot more familiar with emissions from test tubes than from animals. Skunk secretion certainly smelled like a mixture of sodium sulfide and an acid. Such a concoction releases hydrogen sulfide, which accounts for the classic reek of rotten eggs and stink bombs, a smell potent enough to drive away any living creature, and quickly. Which, of course, is exactly what the skunk has in mind when it lets loose from the little scent glands situated on either side of its rectum. Scientists have long been intrigued by the chemical composition of skunk aroma. Way back in 1862, the famous German chemist Friedrich Wohler received a gift of "Nordamerikanischen Stinkthiers" fluid from a "freunde in Neuyork." The stuff was too smelly for the great man to work with, so he gave it to one of his underlings, identified only as Dr. Swarts of Ghent. Swarts carried out the first analysis of skunk secretion and found it to be a complex mixture of many substances that distilled at different temperatures. He was able to determine, however, that the element sulfur was prevalent in the mixture, making up some 16 percent of its weight. There was a price to pay for this enlightenment: Wohler claimed that his assistant's health had been adversely affected. Although chemists have been working on the problem of the exact composition of skunk secretions for over a hundred years, only recently have the specific smelly compounds been identified. This type of research is fraught with difficulty. First of all, how does one procure a sample? Very carefully. Skunks are trapped and anesthetized with ether. A blunt needle is then inserted into the anal sac of the animal and the contents removed by means of a syringe. This sample is subjected to analysis through an instrumental technique known as gas chromatography-mass spectrometry, which separates and identifies the components of a mixture. Literally dozens of compounds have been found in skunk extract, with seven having particularly disturbing smells. Trans-2-butene-1-thiol is the major culprit. Now that we know this, what do we do with the knowledge? While skunk research may be academically fascinating, what we really want is a solution to the problem of the inquisitive dog or cat that has learned a lesson the hard way about the consequences of skunk chasing. How can trans-2-butene-1-thiol and its chemical cousins be neutralized? Tomato juice won't do it - that's just a myth. The only thing tomato juice will do is create a mess, leaving us with the added problem of removing tomato juice from clothing, floors, and walls. It will also turn white dogs pink. But despair not: there is a solution, thanks to the creators of the Indiglo watch. The faces of these watches are treated with an electroluminescent material that glows in the dark. An unfortunate by-product of the manufacturing process used to make this luminescent substance is hydrogen sulfide. Not only does this compound smell awful, but it is also poisonous. A materials engineer, Paul Krebaum, working at the plant where the electroluminescent materials were manufactured, developed a technique for eliminating the smell. He designed a system whereby the air was circulated through a solution of concentrated hydrogen peroxide and sodium hydroxide. His idea was based on some interesting chemistry. Krebaum knew that sulfur binds quite readily to oxygen and that these oxidized derivatives are far less likely to smell. Experiments showed that an alkaline solution of hydrogen peroxide readily oxidizes hydrogen sulfide to odor-free sulfate. The problem of the hydrogen sulfide smell in the plant was solved. One day, a colleague of Krebaum's came to work with a woeful tale of an encounter between his dog and a skunk. Krebaurn had never considered the skunk problem before, but he knew that skunk secretions contained thiols. These resembled hydrogen sulfide chemically and should also be oxidized with his reagent. Krebaum knew, however, that he couldn't expose animals to 30 percent hydrogen peroxide.- it's far too dangerous a substance, as is sodium hydroxide. The formula had to be modified. A little experimentation revealed that 3 percent peroxide would work and that the sodium hydroxide could be replaced with baking soda. Finally, a squirt of dishwashing detergent would help lift the skunk fragrance from the fur. Here is the magic formula: take one liter of 3 percent hydrogen peroxide (available at most pharmacies), add one-quarter cup of baking soda and one teaspoon of liquid dishwashing detergent, wash the cat or dog (or child) with this mixture, and rinse with lots of water. Presto! Skunk smell is almost completely eliminated. The latter point is an important one. People who have struggled with tomato juice and have succeeded in reducing skunk smell (not due to a chemical effect but because they have managed physically to rinse away some of the odiferous compounds) often note that the scent comes back. This is because the skunk secretions also contain compounds called thioacetates, which are not particularly smelly but over time react with moisture to form thiols. As the concentration of thiols increases, the skunk aroma returns, but under the mildly alkaline conditions created by the hydrogen peroxide recipe, these thioacetates are immediately converted to thiols, which in turn are oxidized. Therefore, the lingering smell is greatly reduced. Most researchers are interested in eliminating the skunk stench - but not all. Skunk smell is known to keep bears away and to mask the scent of humans. This is of great interest to hunters, because their scent can often drive their prey away. Of course, nobody would want to carry around bottles of skunk extract, even if such a thing were available. The risk of an inadvertent spill would be just too great. But a clever inventor has come up with not one but two solutions to this problem. "Skunk Skreen" comes in two small bottles. One contains a thiol precursor, which forms the stinky compound when it reacts with the alkaline solution contained in the other bottle. When circumstances dictate, moisten a cloth with a few drops from each bottle, and prepare yourself for a powerful skunklike stench. Bear beware! As we know, the stench can also keep humans away, which is what an Alaskan inventor was banking on when he patented a "personal protector" based on skunk smell. Because a person hasn't the time to start combining chemicals when accosted by an attacker, the inventor devised a way to incorporate skunk extract capsules in a plastic card resembling a credit card. In an emergency, all you have to do is point the card at your attacker and bend it, thereby squirting out a stream of stinking liquid. The card is smooth on one side and rough on the other to avoid accidental self-spraying. Sounds good. Presumably, the police would have little trouble tracking the culprit, as the stench would linger for weeks - that is, unless said culprit knows enough to mix hydrogen peroxide with baking soda. .

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