Chemistry – Page 63 – David Bradley

Nothing new under the sun

Concerns about acrylamide, an organic compound formed in foods when they are heavily browned or even burnt have been raised. The compound has worryingly been classified as a probable carcinogen. But acrylamide from cooked foods is very unlikely to be a cause of cancer in humans. Cancer Research UK stated that the notion that eating burnt food would cause cancer is deceived wisdom, a “myth”.

Anyway, for those who think the revelation that carcinogens are formed in the non-enzymic browning reaction known as the Maillard reaction is something new, take a look at the following article I wrote for New Scientist back in the day: Science: Cooking up carcinogens – The chemicals generated in our food, New Scientist vol 127 issue 1729 – 11 August 1990).

Chemical reactions that take place during cooking, baking and preserving generate products that are very important in giving different foods their distinctive aromas and colour. Recently, researchers have discovered that many of these products can reduce the food’s nutritional value, and some can actually be toxic.

Franze Ledl of Stuttgart University and Erwin Schleicher of the academic hospital Munich-Schwabing in West Germany have studied many of the reactions involved, which are known collectively as the Maillard reaction. They believe that the reaction products could cause some diseases, including certain forms of cancer (Angewandte Chemie, International Edition in English, 1990, vol 29, p 565).

Silly molecule of the month

As if to prove chemists have a sense of humour, Bristol University’s Paul May has added a list of unusual, but genuine, chemical names to his Molecule of the Month web site. Among the chemical delicacies are the super-tough compound ‘adamantane’ and its chemical cousin ‘bastardane’ (more formally known as ethano-bridged noradamantane.

Then there’s the soccer-ball shaped ‘buckminsterfullerene’ and the natural product ‘megaphone’ from the roots of the plant Aniba megaphylla. There is even a mineral with the enticing name of ‘cummingtonite’ while the stuttering ‘unununium’ makes an elemental appearance too. But, the choice that May puts at the top of his list is…for the sake of decency…best left to visitors to find for themselves. Suffice to say, it involves the arsenic version of the molecule pyrrole and it’s ring shaped: sillymols.htm.

Stable bonded oxygen

Have you heard of stable bonded oxygen molecules? No? Neither had we until an associate showed us an advert for Aerobic Oxygen.

Apparently, this wonderful stuff can treat multiple sclerosis, asthma, malaria, Parkinson’s disease, cancers, ME, flu, eczema and many other disorders. So claim the manufacturers in their marketing spiel.

The molecules in Aerobic Oxygen ‘will not release themselves until the body has need for them, therefore they travel through the body in a stable form.’ Aside from the obvious pseudoscience and the large drop of snake oil, we wonder why anyone would buy the stuff when there is so much stable bonded oxygen all around us – just enough in each breath to fulfill the body’s needs, in fact.

Weirdly, on the next page of the magazine carrying the advert, we were startled to find another, this time, marketing a product for improving eye health. The Visionace nutrient capsules from Vitabiotics apparently ‘help maintain healthy eyes and vision’ and the ‘formula’ includes ‘important antioxidant nutrients like ”natural” carotenoids, vitamin C and bioflavonoids in common with lots of other health supplements.

We began to imagine the consequences of matter colliding with antimatter, and wondered what terrible health effects might befall any one taking Aerobic Oxygen at the same time as these antioxidant capsules. Perhaps they would simply cancel each other out in a flash of the credit card. Now, take a deep breath, count to ten…and relax.

Really cookin’

Pizza

Most chemists now agree that microwaves are not doing anything mysterious to chemicals. They are simply another form of electromagnetic radiation, like light, infra-red or radio waves.

Microwaves have a wavelength between 1 mm and 0.1 m (corresponding to a frequency of 300 to 3 GHz). At these wavelengths the electromagnetic energy interacts with polar molecules, such as water, making them spin. The spinning water molecules knock into each other and pass on their rotational energy by making their neighbours vibrate. The more molecules vibrate the hotter they get.

But, while there is nothing mystical about this, the process of microwave heating means that the energy is transferred to the molecules more effectively than simply heating them in a flask with a Bunsen burner so that the reactions generally go faster.

The formation of hot spots in a reaction mixture means that there are also very sharp rises in temperature without the solvent having a chance to boil away. Water, for instance, can reach 105 Celsius before boiling in such a hot spot in the microwave. The common organic solvent acetonitrile can reach 38 degrees above its normal boiling point.

Since most reaction rates are accelerated by increasing the reaction temperature – a ten-degree rise in temperature, doubles the reaction rate – a hot spot at a temperature above the normal boiling point of the reaction solvent means a microwave reaction can be that much faster.

Koala breath

We might all soon be making like koalas to keep our breath fresh and our teeth free of decay, according to Japanese researchers.

Kenji Osawa and his colleagues at Lotte Central Laboratory Ltd in Saitama and at Tokyo University of Pharmacy and Life Sciences have extracted a group of novel compounds from eucalyptus leaves that can knock out the typical bacteria that cause plaque build-up on teeth that leads unchecked to tooth decay. And, if you doubt it will work ask yourself, if you have ever seen a koala in a dentist’s chair. I rest my case.

Copious water

This particularly wet undergraduate was wandering aimlessly round the lab peering into fume-cupboards and scouring shelves of flasks and bottles, obviously looking for some vital reagent for their experiment.

Dr Helpfull Graduatestudentisch approached the rookie and asked what he was after. ‘Copious water’, was the reply, ‘it says use copious water to cool the reaction…so I was looking for the flask’.

Hearing of this, the resourceful lab technician printed off some labels for the distilled water bottles – ‘COPIOUS WATER: Use sparingly’. Take heed, they’ll be bottling it at source pumping in CO2 under pressure and charging for that hydrated dihydrogen monoxide next you know!

What’s in a chemical name

If you think picking a name for a baby or pet cat is hard take a look at the Nature Biotechnology archives, there you will find all sorts of options for choosing the name for the latest discovered genetic variants of Drosophila melanogaster, the molecular biologist’s favourite fly.

The latest batch of Drosophila with spines have lovingly named proteins such as hedgehogs and variations on the theme are Indian, Desert and Sonic hedgehog [[computer games pervade all walks of life]]. There are many more monikers for fly proteins to choose from such as four-wheel drive, prawny abdomen, and twisted genitalia – all of these somehow describe characteristics of the proteins in question although pity the poor fly with the latter name.

Coming up with such a witty and humorous name for a choice molecule is even harder for yeast, or Caenorhabditis elegans, researchers who by international convention are stuck with three terse letters and a digit.

Chemists, of course, retain the crown for thinking up easy to remember names, a boon for attracting new students into the field. For instance, a recent news item in New Scientist described the wonders of a toroidal molecule with the easy to swallow name of {4,34-dimethyl-1,4,7,10,13,16,19,22,25,28,31,34,37,40,43,46,49,52,55,5
-icosaazatricyclo[56.2.2.2.2.2.7,10,28,31,37,40]hexacontane. Then again “bagel-ane” was probably a bit too sweet.

Clams on Prozac

The sex connection with oysters (I don’t mean sex with them, obviously, but that they’re supposed to be an aphrodisiac) is obvious but what about clams on Prozac?

A US biologist claimed to have discovered that the anti-depressant can help improve the sex lives of shellfish. According to Peter Fong of Gettysberg College he found that the drug stimulates freshwater fingernail clams and zebra mussels to spawn, which could be useful for clam and mussel farmers. A clue as to why lies in the effects of Prozac on raising serotonin levels – the compound not only affects human mental happiness but is the trigger for spawning in these creatures.

Fong added mysteriously that rarely has either animal been observed to spawn in the wild or in the laboratory without the use of an artificial chemical aid. I was puzzled then as to how these aquatic creatures managed to reproduce successfully for millions of years before the invention of Prozac.

Guilty privates

There’s an army barracks attached to a local village that allows the public to use its heated outdoor swimming pool in the summer. I often assumed it was too much chlorine that was the problem with stinging eyes.

But, according to chemist Howard Gosling that typical swimming pool smell actually comes from compounds known as chloramines that form when chlorine reacts with any urine or sweat in the water. Nice. It’s the chloramines not the chlorine that make your eyes sting.

I’ll leave you to draw your own conclusions about why the army pool brings tears to the eyes. Maybe the CO should drop in some of that chemical that turns the water blue of there are any guilty privates swimming.

Illicit CD-ROMs

An Australian chemist friend of mine was giving a lecture recently on how Western chemists might best help their colleagues in the developing world gain access to the mountains of chemical information available without eating into their own budgets too much.

Various systems based around the Web were discussed but industrial delegates were surprisingly more than a little interested in one particular idea concerning CD-ROMs.

My chemist friend planned to set up a cheap subscription service for a monthly CD-ROM that would mirror chemistry sites on the web and so bring the internet to those scientists in poverty-struck institutes with no access. When the queue for samples of the CD-ROM had stretched to the back of the lecture hall my friend asked the next person in line why they were so keen to see the CD-ROM. The startling reply was that their employer was so scared of staff wasting time on the web that all net access was blocked – a CD-ROM could be viewed illicitly without needing a net connection.