chemmatters october 2004

OCTOBER 2004

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Question From the Classroom 4Should soda vending machines in school be banned? You can test the sugar content in your favorite beverage with an activity that relates density to sugar content.

Carb Crazy 6Low-carb diets and products are everywhere. What are carbs and why are some people cutting down on them?

Lab on a Stick 9Meet the tiny paper strip with two enzymes and 16 reagents that can perform 10 urinalysis tests in under twominutes and help diagnose a host of medical conditions.

ChemHistoryCleopatras Perfume Factory and Day Spa 13The famous young queen owned a perfume factoryand recorded recipes for early cosmeticsmany of which used early chemical techniques.

MysteryMattersWhen Good Science Goes Bad! 16

Did a mother really poison her baby with ethylene glycol?

ChemShorts 19In this edition: New high-tech bandages made from shrimpshells and a tiny sensor that gives blood glucose levels.

Chem.matters.links 20

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4 ChemMatters, OCTOBER 2004

By Bob Becker

Q. Why are some schools considering a ban on soda machines?They are in stores and offices all over town. Why should the schoolbe any different? Besides, whats wrong with soda anyway?

A. This is certainly a hot topic right now inmany state legislatures and at many schooldistrict board meetings. On the one hand,soda vending machines are bringing in much-needed money for schools. And in recentyears, beverage companies have started offer-ing even more lucrative contracts for schoolsthat allow only their product to be sold. Theseadded bonuses may have helped pay for thenew landscaping at your school, or perhapsthe new scoreboard for the football field.Schools have grown increasingly dependenton these funds and mostadministrators consider thesevending machines essentialsources of income for theschools budget.

At the forefront of thecontroversy is a molecule com-posed of 6 carbon atoms, 12hydrogen atoms, and 6 oxygenatoms: C6H12O6also knownas fructose, the sugar mostcommonly used in carbonatedbeverages. There are 40 gramsof sugar in a typical 12 oz sodacan, 67 grams in a 20 oz bottle.

All this added sugar in astudents diet translates into extra Calories.Combine this increase in Calorie intake with ageneral decline in physical activity, and theoutcome is scary: Thirty years ago, the aver-age American consumed 85 L of soda peryear. One teenager in 17 was overweight.Today, the average American consumes over220 L of soda per year, and one teenager inseven is overweight. Furthermore, soda offersvirtually nothing in the way of nutritionalvalue: no vitamins or minerals. When yourparents were in high school, the averageteenager drank twice as much milk as soda.Today that statistic has completely flippedaround, with twice as much soda consumedas milk. This has prompted some healthexperts to nickname soda liquid candy, and

has prompted some states toconsider banning sales of sodain public schools, especially atthe elementary level.

Soda proponents haveargued that although soda con-sumption may have increasedover the past few decades andobesity may have gone up aswell, that does not mean thatthe extra soda was responsible. Certainly,many other factors have contributed to therise in obesity, from a decline in physical

activity to an increased preference forsuper-sized burgers and fries.

But what if you are concernedabout sugar intake? How could youdetermine the sugar contents ofsome of your favorite beverages?The total carbohydrates percent-age listed on the label is a goodplace to start, but is there a simpleway to verify these values, so youdont have to take the beveragecompanies word for it? When

chemists want to measure a quantity orvalue such as sugar content, they often

do so by indirect meansmeasuring insteada related property and then comparing that tothe values for prepared standardized sam-ples. For sugar content, the most easily cor-related property is that of density.

Density, as you may have already learnedin class, is the ratio of a substances mass toits volume: (D = m/V). In other words, densityis the concentration of matter: how muchmaterial is compacted into how much space.Sugarwater solutions tend to have a slightlyhigher density than pure water, and the moresugar, the higher the density. This is true ofmost substances dissolved in water, but sincesugar is by far the most abundant solute inmost beverages, sugar content and densityshould show the highest correlation.

Question From the Classroom

The Great Soda Sellout

What 67 and 40 gramsof sugar look like!

www.chemistry.org/education/chemmatters.html

Whats going on here? Now the C2 cola is floating inthe middle of the vase. What happened? Its thesame can. Whats changed? The answer is on ourback page.

Wowdensity in action! Regular Cokesinks, but the new C2 (half-the-sugarcola) floats because its overall density isless than water (< 1.0 g/cm3).

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So, how well do youknow the sugar con-tent of the beveragesyou drink?Rank the following four beverages from lowestsugar content to highest: Coke, Welchs 100%grape juice, Powerade, and orange soda.

Along with adding Calories to a beverage,dissolved sugar also increases the density ofthe solution. In this activity, you will first deter-mine the density of five known (standardized)sugar solutions: 0% (which is just plain water),5%, 10%, 15%, and 20%. You will then plotthese densities on a density vs. sugar contentgraph. Finally, you will determine the densitiesof the four beverages, and then use the graphto approximate their sugar contents.

Safety note: Never drink a beveragethat has been opened or used in the laboratory(or has been put in laboratory glassware). Dis-card all your solutions down the sink.

You will need: A cola, grape juice, sports beverage, and

orange soda. Note: Carbonated beveragesshould be decarbonated (made flat) bypouring them back and forth several timesbetween two cups and setting them outovernight.

Standardized sugar solutions: 0%, 5%,10%, 15%, and 20%. For example, tomake up 5% sugar solution, dissolve 5 gof table sugar in 95 g of water. Note: Thesugar found in soda is usually fructose;however, table sugar is sucrose. Sincesucrose and fructose solutions have verysimilar densities, this substitution willhave very little impact on your results.

10-mL volumetric pipet and bulb. 100-mL beaker. Electronic balance, paper towels, and

graph paper.

What to do:Your teacher will demon-

strate the proper technique forusing a volumetric pipet.

1. Place the beaker on thebalance and hit thetare (rezero) button.The scale should read0.00 g. Draw up a pre-cisely measured 10.00mL of 0% sugarsolution into thepipet. Thenempty it intothe beaker,touching thetip of thepipet to theinside wall ofthe beaker tohelp get out mostof the liquid in the tip.Do not try to shake outany liquid that remainsthere. The pipets aredesigned TD (todeliver) 10.00 mL andthat remaining dropshould not be squeezedout. Since the beakerhas already been zeroedout, the mass is that ofthe liquid alone. Recordthis mass reading, thenpush the tare button to rezero thescale for the next reading.

2. Touch the pipet to a paper towel to getrid of the excess liquid in the tip. Repeatstep 1 with each of the remaining sugarsolutions, and then with each of the fourbeverages. Do not put any of the solu-tions back into the cups from which theycame, just leave them in the beaker.When the beaker gets full, simply emptyit into the sink, set it back on the scale,and push the tare button.

3. Calculate the density of each solution.Because the volume is always 10.00 mL,this should be easy.

4. Carefully plot your calculated densitiesversus sugar content (%) for each of thefive sugar solutions. Then use a ruler todraw a best-fit straight line through thepoint (DO NOT PLAY CONNECT-THE-DOTS!!!). Then use the densities of thefour beverages to approximate theirsugar contents. To do this, start on they axis at a density of one of the bever-ages; then follow the line over to whereit hits the best fit line you drew; then gostraight down to the x axis to determinethe corresponding sugar content value.


TRY THIS!

The results might surprise you!

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No-Carb?Low-Carb?High-Carb?

Never before has the roleof carbohydrates in ourdiet been so thoroughly

discussed. Well try to cut

through the hype to

give you the

lowdownon...

By Brian Rohrig


What are carbs?

The word carbohydrate reveals that all carbs are composed ofthree elements: carbon, hydrogen, and oxygen. There arethree main categories of carbohydratesmonosaccharides,disaccharides, and polysaccharides.

Monosaccharides are composed of one sugar unit and arereferred to as simple sugars. Their empirical formula is generallyCH2O. Some common monosaccharides are glucose and fructose.Although both have a formula of C6H12O6, they have a differentarrangement of atoms. Such compounds are called isomers. Glucoseis produced by plants during photosynthesis. Glucose can be found

in sports drinks, providing quick energy whenyou need it. Glucose is the bodys primary fuelsource. It is broken down into energy throughthe process of cellular respiration. Carbondioxide is released as a waste product. If glu-cose is not converted into energy, it is con-verted into glycogen to be stored.

Disaccharides, also known as doublesugars, are composed of two simple sugarmolecules. The most common disaccharide issucrose or table sugar. In order to be used byour body as energy, sucrose must first be bro-ken down into glucose and fructose. Food

manufacturers are more often replacing sucrose in products with fruc-tose, because it is cheaper to produce, andbecause it is sweeter, less needs to beused. Other common disaccharides aremaltose and lactose (milk sugar).

Polysaccharides are complex carbo-hydrates. They are polymers composed oflong chains of sugar units. A commonpolysaccharide is starch, which is composed of long chains of glucosemolecules. Starch is used by plants as a way to store energy, and it canbe found in foods such as potatoes, rice, corn, and wheat. Our bodymust break down starch into glucose, which it then uses for energy.

Other types of complex carbohydrates are not digestible by ourbody. Chief among these are cellulose, which forms the cell walls ofplant cells, giving them structure and support. Its glucose molecules arelinked together in such a way that our body lacks the necessaryenzymes to break them down. These indigestible polysaccharides areknown as fiber, and they contribute no calories because our bodies can-not convert them into energy. High-fiber foodssuch as oats, bran,and whole grainsare an essential part of our diet, aiding in digestion.

Carbohydrates and blood sugarTo understand the effect of carbohydrates on our body, it is impor-

tant to understand their role on blood sugar. Just like a car requires fuel,so does our body. The bodys major fuel source is glucose, or bloodsugar. However, this blood sugar is not automatically released into thecells. If a cars engine receives too much fuel, the engine becomesflooded, and it will not start. In the same way, the body must regulatehow much blood sugar enters our cells. This occurs through the pro-duction of the hormone insulin, which is manufactured by the pancreas.Think of insulin as the gatekeeper to the cellsit opens the gates andallows glucose to leave the bloodstream and enter our cells.

Once sugar enters our cells, it can do one of three things. It can beconverted into energy through cellular respiration. Or it can be con-verted into glycogen in the liver and muscles, for use as an emergencyfuel. Glycogen is similar to starch but is more extensively branched.Finally, it can be converted into fat if there is more sugar available thanis needed.

Consider what happens when you wash down a glazed doughnutwith a sugary soda. As your bloodstream is inundated with sugar, atemporary spike in blood sugar will occur. Your pancreas responds byproducing a surge of insulin to quickly rid the bloodstream of thisexcess sugar. This quick release of insulin will cause your blood sugarto then drop suddenly. The sudden drop in blood sugar can cause weak-ness, fatigue, and intense hungeroften leading to a craving for more

delicious glazed donuts. This can create a vicious cycle,where our blood sugar constantly rises and falls, leadingto overeating and eventual weight gain. A well-balanceddiet can help to reduce these sudden peaks and falls inblood sugar.

Over the long term, constant spikes in blood sugarand insulin are not a good thing. When so much insulin

is produced for so long, your body may become immune to the effectsof it, creating a condition known as insulin resistanceoften a precur-sor to type 2 diabetes. For rea-sons not yet fully understood,the cells can become desensi-tized to the effects of insulin,with the result that glucose isnot effectively taken into thecells and converted into energy.The liver then takes over, takingthis excess blood sugar andconverting it into fatleading to obesity. And the overworked pancreasmay get worn out from producing so much insulin.

Why not radically cut carbohydrates from the diet?

Eat as much bacon and eggs as you want as long as you forgetabout the toast and orange juice?! Such a suggestion is at the very leastculinary, if not dietary, heresy. But as a result of two decades of risingobesity rates and the sheer popularity of low-carb diets, researchers,doctors, and dietitians began re-examining the theories of Dr. RobertAtkins, who published Dr. Atkins Diet Revolution in 1972. He advocatedeating all of the fats and proteins you wanted, and said that if you onlycut out all those carbohydrates, you would lose weight.

H

HOCH2

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H

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OH

O H

O

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HOCH2

HOH H

H OH

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O

H H

HOCH2

HOH H

H OH

O

O

H

H

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HOH H

H

HO

OH

O H

O

H H

HOCH2

HOH H

H OH

O H

O

H H

HOCH2

HOH H

H OH

O H

O

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HOCH2

HOH H

H OH

O H

O

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CH2

HOH H

H OH

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The polysaccharide glycogen is a stored form of glucose.

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O

Sucrose

Glucose

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Fructose

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In the United States one teen in seven is

overweight.DA

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SOURCE: SURGEON GENERAL

8 ChemMatters, OCTOBER 2004 www.chemistry.org/education/chemmatters.html

L

Numerous modifications of the Atkinsdiet, such as the South Beach Diet and theZone, have since appeared. Many of thesemodified diets have a more balancedapproach, stressing the importance ofavoiding unhealthy saturated fats found inred meat and dairy products, and empha-sizing healthier unsaturated fats found innuts, fish, and vegetable oils.

Millions have tried the diet with suc-cess and testimonials abound. By now,

youve probably heard a friend or family member give the low-carbdieter litany: I failed on other diets, but this diet worked for mebecause I wasnt hungry all the time. I lost weight faster than onother diets, and I wasnt hungry all the time. Or even, I failed on thisdiet, but at least I wasnt hungry all the time!

How do low-carb diets work?All diets work according to one basic principle: You

must burn more calories than you consume. How manycalories you burn depends on both metabolism and exer-cise. You cannot lose weight if you consume more caloriesthan your body uses. By cutting out carbs, you are cuttingback on a lot of calories. Cutting out just sugared sodas,potato chips, and candy bars can reduce your overall calo-rie consumption dramatically.

Another reason low-carb diets are successful is thatfats and protein have better staying power. Because car-bohydrates are rapidly converted into glucose and then uti-lized by your body as energy, they do not keep us satiatedfor long. Fat and protein are absorbed more slowly by thebody, so they stay with us longer. Even though low-carbdiets claim you can eat all the fat and protein you want, intruth these foods fill us quicker, causing us to ultimatelyeat less.

Ketosis: An inefficient way to burn fat

Although some claim that a reduced-carbohydrate dietis nothing more than a reduced-calorie diet in disguise,low-carb diets actually do one thing that is radically differ-ent than any other diet. The majority eliminate most, if notall, carbohydrates in the initial induction phase of the diet.When the body becomes carbohydrate-starved, it must findan alternate energy source.

The first source it taps is the glycogen found in theliver and muscle. But the bodys glycogen stores can only last about twodays. After this, our body turns to fat for energy. However, the break-down of fat in this case does not produce glucose. Instead, the fat isbroken down into ketones, through an unusual process known as keto-sis. Normally, people burn fats without making ketones. Ketosis onlyoccurs when people are carbohydrate-starved.

During ketosis, fat is not completely broken down and you dontreceive the normal caloric value from burning it. The excess ketonesproduced during ketosis are secreted in our urine and breath. Some-times this gives your breath a fruity odor, since acetonea ketone

may be released by the breath during ketosis. Because the kidneys flushout these ketones from the body, it is important to drink a lot of water

on a low-carb diet. Dieters often confirmtheir body is in ketosis by checking theirurine with ketone test strips (see Lab on aStick in this issue).

Considerable debate has arisenamong medical experts as to whether ornot ketosis is dangerous. Some confuseketosis with a more serious condition

known as ketoacidosis, which is an extreme form of ketosis sometimessuffered by type 1 diabetics. During ketoacidosis, the pH of the bloodfalls to dangerous levels, because of excessive buildup of acidicketones. This can lead to coma and death if left untreated.

Some argue that the body functions even better when usingketones as fuel. Others claim that the brain cannot function as well onketones, and the body will turn to muscle and organ tissue to try toscavenge glucose for fuel. However, most medical authorities today are

leaning toward the view that ketosis is a safe bodily processas long as ketones are not produced faster than the bodycan get rid of them.

Are low-carb diets good for you?

The low-carb diet phenomenon is still too new tojudge its long-term effects. However, two studies recentlypublished in the New England Journal of Medicine offeredsome promising news for adult low-carb dieters. Thesestudies found that partici-pants who lost weight onlow-carb diets had higherlevels of HDL (good) cho-lesterol and lower levelsof triglycerides, or fats,than those who lostweight on different diets.

Theres no specific research on teenagers, but youshould be wary of going on the diet, especially if you arestill growing. Many participants sacrifice the health benefitsof the nutrients found in milk, fruit, and whole grains.Osteoporosis can result from a long-term deficiency of cal-cium in the diet, which could result if milk was totally elimi-nated from the diet. Pregnant women should definitely notbe on the diet, because the developing fetus can be harmedby the lack of nutrients. Athletes should also avoid low-carb diets, since peak athletic performance is dependant on

the quick availability of glucose for energy, as well as relying on glyco-gen reserves.

Any diet is only as successful as the ability to remain on it for life.And make sure you incorporate plenty of exercise in any weight-lossplan you choose.

OCCH3 C

O

O

CH2

Acetoacetate(a ketone body)

All dietswork

according toone basicprinciple:You mustburn morecaloriesthan youconsume.

Brian Rohrig is a chemistry teacher at Jonathan Alder High School in Plain City,OH. His last article for ChemMatters, Lightning: Natures Deadly Fireworksappeared in the April 2004 issue.

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Imagine that you have just swallowed a rich anddelicious chunk of sweet chocolate cake. Min-utes later, carbohydrates from that cake willbecome glucose, the sugar your cells use forenergy. If youre healthy, a hormone called insulin,produced by islet cells in your pancreas, will snatchglucose from your bloodstream and squirrel it awayinside your liver and muscle cells in long chains forfuture use. But if you have diabetes, your bodyeither doesnt make insulin (type I), or is no longersensitive to its effects (type II), allowing glucose tobuild up in the bloodstream.

High blood sugar levels can be toxic to manytypes of cells, leading to poor circulation, kidney fail-ure, blindness, or worse. Normally, the body natu-rally regulates the amount of insulin and a counter-acting hormone called glucagon to keep blood sugarin check. Diabetics can keep their blood sugar undercontrol by taking insulin or regulating their diets. But

theres only one catchto know how much insulinto take or how to modify what they eat, people withdiabetes need a way to keep track of exactly howhigh their blood sugar levels are.

Researchers struggled for decades todevelop a test for glucose in urine that was easyenough for anyone to use. But it wasnt until the1950s that former American Chemical Societypresident Helen Free and her husband, Al, devel-oped the dip-and-read test strips called Clinistix.The tests were such an advance that researchershave since combined 10 urine teststo check forailments like liver failure, urinary tract infections,and othersonto one plastic stick. Its like havinga team of chemists instantaneously at your dis-posal. For such a simple idea, urine dipsticks haverevolutionized diabetes care and modern urinaly-sis. But just how did the Frees develop this Labon a Stick?


LAB ON A STICKWithin two minutes, one tiny strip, with two enzymes and 16 reagents,can perform 10 tests that help diagnose a host of medical conditions.

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Most people with

type 1 diabetes are

first diagnosed

during their teen

years. In the

United States,

more than 400,000

new cases of

diabetes are

reported every

year.

By Christen Brownlee

10 ChemMatters, FEBRUARY 2004 www.chemistry.org/education/chemmatters.html

A rainbow of testsResearchers have known for thousands of years that diabetics

excrete sugar into their urinea side effect of overwhelming the kid-neys with too much blood glucose. So, in one of thefirst tests for diabetes, doctors pouredurine on the ground to see whether itattracted insects. If insects crowded aroundthe puddle, it meant they were attracted tosugar, a dead giveaway for diabetes.

Although this test was helpful for deter-mining whether a patient had diabetes, itwasnt sensitive enough to detect how muchsugar was present in the urine, an indicatorof diabetes severity. So, in the early 1900s,researchers developed a method to estimatethe level of glucose in urine. Doctors mixed ablue solution of cupric sulfate (CuSO4) into aurine sample, then put in some alkali (strongbase) and a complexing agent such as tartrateor ammonia to prevent precipitation ofcopper(II) hydroxide. Heating the mixture overa Bunsen burner or in a water bath caused anyglucose, a strong reducing (electron donating) substance, to react withthe blue cupric ions, changing them to copper(I), which precipitates asthe orange-brown copper(I) oxide. The extent of the mixtures colorchangefrom blue to green, brown, and redgave doctors a rough

estimate of how much glucose was in a patients blood. The test wascolorimetricit relied on a visible color change to track the presenceof a chemical.

This analysis was better than pouring urine on the ground, but notgreat. It still required special equipment, harsh chemicals, and plentyof know-how to judge the results. In the 1930s, Walter Compton, thedoctor whose family helped found Miles Laboratories, developed animproved version of the same test, with a lot of less mess and effort.He made a tablet with cupric sulfate, sodium hydroxide (the strongbase), and citric acid, which he dubbed Clinitest. After putting the tabletin a test tube and adding several drops of water, it fizzed like AlkaSeltzer. Heat from the reaction allowed any glucose present to reducethe cupric ions, and doctors compared the remaining mixtures color toa chart to determine the urines glucose level.

Clinitest was easy enough for some diabetics to use outside thedoctors office, but it still wasnt perfect. Scientists knew that manychemicals, including some drugs, act as reducing substance in urine.So, patients with normal blood glucose levels frequently ended up withfalse positive results for diabetes. To weed out these bogus results,Helen and Al Free, along with other chemists at Miles Laboratories,developed a tablet test for ketone bodies, a byproduct in diabeticsurine caused by metabolizing fat instead of glucose. The white tabletcontained alkali and nitroprusside, [Fe(CN)5(NO)]2-. If a drop of urineturned the tablet purple, the patient had diabetes.

Put it on paperFor years, doctors had to perform both tests and a blood test to

get an accurate reading of a patients blood sugar. But in 1953, dia-betes diagnostics took a giant leap ahead. A factory owned by MilesLaboratories developed an enzyme called glucose oxidase, whichreacted only with glucose. Al Free immediately noticed the potential for

a brand new type of glucose test.When glucose oxidase reacts withglucose, it forms two products,gluconic acid and hydrogen perox-ide. Testing for gluconic acidproved too tricky for easy analy-sis, so the Miles chemists focusedon a reaction to show the pres-ence of hydrogen peroxideinstead. The researchers addedperoxidase to react with hydro-gen peroxide, as well as a benzi-dine, a type of chromogen, orchemical that changes colorwhen it becomes oxidized.

The reaction worked like acharm, turning shades of bluewith different glucose levels.

But the test was still too compli-cated for most diabetics to use at home. After doing thousands of testson spot plates and in test tubes, Al had an ideaif the same reagentswere on a piece of paper, could you dip it into a urine sample and getthe same results? After many more tests, the researchers found thatthe answer was yes.

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Helen and Al Free share a moment with a lab rat at the Miles-AmesResearch Laboratory in 1948.


Ten tests in oneBut the Frees and a hundred other researchers at the Miles Ames

Research Laboratory couldnt stop quite yet. They developed a colori-metric paper test for albumin, a plasma protein that leaks into diabet-ics urine when their kidneys fail. Since doctors frequently test forglucose and albumin at the same time, they decided to put the twotests on the same paper strip. They later incorporated the ketone testand added colorimetric analysesfor bilirubin and urobilinogen,byproducts formed by the break-down of red blood cells andgood indicators for liver failure.Later came tests on the samestrip for occult (hidden) bloodand proteintwo signs of kid-ney damageas well asleukocytes and nitrite, signsof a urinary tract infection.The researchers rounded offthe strips with reagents forpH and specific gravity, ameasure of concentration.

The test strips wereso easy to use that theybecame an instant hit anda big seller for the Ames divisionof Miles Laboratory (later to become Bayer). Clinical lab person-nel simply dipped a strip into urine samples for a practically instant uri-nalysis, a window into diabetic, liver, or urinary tract health. Today,Bayer sells several varieties of urine dip-and-read tests, including spe-cial diabetic test strips, with just glucose and ketone tests, as well asstrips called Multistix-10SG, with all 10 tests. Helen Free, still a consul-tant for Bayer, says that she frequently meets people her work hashelped. Theyll say, My mother used those strips, or My grandfatherdid, she said. Its a wonderful feeling, knowing that your workchanged peoples livesit gives me shivers when I think about it.

Glucose(diabetes)

Teachers!Remember the free Teachers Guide

(chemistry.org/education/

chemmatters.html) for

Lab on a Stick student

questions, additional

information, and activities!

Colorimetric Test. Just like the universal pH paper you might have used inlab, readings for the Multistix-10SG are made by comparing the strip to acolor chart on the container.

Leukocytes (urinary tract

infections)Nitrite

(urinary tract infections)

Urobilinogen(liver damage)

Protein(kidney diseases)

pH (acid-base balance off, infections)

Blood(kidney diseases)

Specific gravity (dehydration)

Ketone(diabetes, starvation,

and related conditions)Bilirubin

(liver damage)

Special interview with Helen Free on the next page!

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Q&AWithHelenFree

How did youdecide to becomea chemist?

My English teacher inhigh school, Miss Johnson,was my role model, and so Iwas going to be a Latin orEnglish teacher. Then inDecember, the bombing ofPearl Harbor happened, set-ting off World War II. Inorder to avoid being draftedinto the army, all the guyswent out and joined up forthe navy or the air force orwherever, and left college.We had house mothers inour college dorms back inthose days, and our housemothers name was HarrietKline. At dinner one night,she said, You know, girls,youre going to have to takesome science, because wedont know how long thiswar will last or when theguys will come back. Sheturned to me and said,You're taking chemistry,arent you, Helen? Do youlike it? Are you getting goodgrades? I answered yes toall of her questions. Thenshe asked, Why don't youswitch majors? And I saidokay. Boom, it happened justlike that. It was a turningpoint, and such a lucky onethat it happened.

How did youmeet your hus-band, Al Free?

I was hired in the con-trol lab of Miles Laboratories,which is now Bayer, in 1944.At the time, we were devisingmethods to determine theamount of each vitamin in amultivitamin tablet, soeach tabletwould havethe sameamount.After weestablishedthe method,we were justanalyzing vit-amins dayafter day, andit got to betoo routine. Ikept bugging them to let mego into the research lab,because I thought researchsounded like a glamorousthing to do. I was not offeredthe job in the research labuntil 1946, after Miles hadexpanded, so they had a bio-chemistry lab. Al Free camefrom Cleveland to run thenew lab. He was a professorof biochemistry at WesternReserve Medical School. Myco-workers encouraged meto go interview with Al Free,so that maybe he would hire

me. And he did. Two yearslater, I married the bossitwas one of the smartestthings I ever did. We made ateam; we were married 53years, and we just workedtogether and had a goodtime the whole time.

Did you get special treatmentbecause you weremarried to theboss?

No, in fact, Al bent overbackwards not to give methe plush experiments. Hegave me experiments work-ing with blood and tears andstools and all that kind ofstuff.

How many patentshave you held foryour research? Didyou earn extramoney at Miles foreach patent?

Ive held just sevenpatents, and there were awhole bunch of people whocontributed to each oneitwasnt just Al and me. Imade a dollar for each

patent. People often will tellme, Oh, thats terrible! ButI say, well, thats what Mileshired us to do. If you work ina research lab, youre sup-posed to invent things.Thats your job. They payyou a salary, and they payyour salary even if you dontinvent anything. So, why giveyou more if one of the thingshappens to earn a patent?

What advice wouldyou give someonewho is thinking ofpursuing chem-istry?

You can do a whole lotof other things besides work-ing in a lab if you have a sci-ence degreeits going tohelp you in no matter whatkind of career you choose.The scientific approach tosolving problems is helpfulin almost any area of yourlife. If you do choose to dostraight chemistry, they needchemists not only in theresearch lab and in the con-trol laboratory, but they needchemists in manufacturingand chemists in the legaldepartments. People dontunderstand how importantthe field is. If you get anopportunity like I did to jumpinto a field you like, grabhold of it and take it. And ifyou work in a lab and decidethat you dont like it, get outand do something else. Theworld is your oyster nowa-daysthere are so manykinds of jobs that you cando. I dont see how kids evermake up their minds.

Christen Brownlee is a freelance science writer living in Washington,DC. Her last article, Four Cool Chemistry Jobs, appeared in theDecember 2003 issue of ChemMatters.

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Helen Free demonstrates the use of Hemastix andCombistix at a 1940s AMA meeting.

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ChemHistory

Package 1: The Cleopatra45 silver denarii

*Package includes full use of the spas facilities

and your choice of three of the following:

DEAD SEA MUD BODY POLISH deepcleans, purifies, and restores your skin, leaving

you feeling smooth and radiant all over.

CROC EXCRETA FACIAL tightens the poresand stimulates circulation so your skin is left with

a smooth, healthy glow.

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MORINGA MANICURE leaves your handsfeeling fresh and revitalized, not greasy.

ASS-MILK BATH nourishes the skin and leaves it feeling soft and lithe.

OUR SIGNATURE MAKEOVER includes expertly

applied green malachite and black galena eyeliner,

red ocher and henna body paint, finishing with

our exclusive crushed beetle-shell glitter for that

Cleopatra look your own Mark Antony will love.

Package 2: The Mark Antony30 silver denarii

*Package includes full use of the Cleopatra Day

Spa facilities and your choice of two

of the following:

DEAD SEA MUD BATH relieves aches andpains, reduces stiffness and muscle tension after

exercise, and revitalizes the skin. Enriched with

Dead Sea salts, our mud has a young,

masculine fragrance.

ASPHALITE HAIR PACK alleviates dandruffand normalizes oily hair. Makes hair feel

revitalized and moisturized. It will not overdry

the scalp.

DEAD SEA SALT FOOT SCRUB is just thething after marching with your legions.

HORSERADISH BODY POLISH revitalizesyour skin without that smelly, greasy afterfeel.

BLACK-TAR MASK draws out toxins to clear up

unsightly facial blemishes, purifies,

and revitalizes the complexion.


Nestled at the south end of the Dead Sea,Cleopatras Day Spa is more than just arelaxing destination. It is an intoxicating

experience designed to provide an escapefrom the pressures of everyday life.

We hold an unmatched reputation and anelite clienteleMark Antony marched hisarmy to the Dead Sea to secure the spa for

beautiful Queen Cleopatra. If our ser-vices work for a Queen and RomanConsul, just imagine what theyll do

for your health and wellness. Speciallytrained therapists assess your current

level of fitness and discuss your goals. Our most popular packages:


By Lois Fruen

These real treatments from ourfictional ancient spa brochure,(on the previous page), may notseem appealing, but they weresought after in ancient times, and manyare still available today, albeit with differ-ent names. It was Cleopatra, the famousqueen of Egypt, who popularized skincare treatments in her book titled Cleopa-tra Gynaeciarum Libri. There, sherecorded recipes for making cosmeticsand perfumed ointments. She was sointerested in spa treatments and per-fumes that her lover, Mark Antony, gaveher the gift of a spa and perfume factorythat had been built by Herod the Great atthe south end of the Dead Sea.

Asphaltskin care

Archaeologistsunearthed jars atCleopatras spa thatcontained residues ofancient skincare productsthat Cleopatra likely used.When chemists analyzed the residue fromone jar of Dead Sea mud treat-ment, they were sur-prised to find it had asimilar chemical compo-sition to asphalt, betterknown as tar or pitch, acomplex mixture of highmolecular weight hydrocar-bons, with partially oxidizedand sulfur-containing com-pounds mixed in for goodmeasure. Their analysis wasconfirmed by Pliny the Elder, afirst-century AD historian, whose historiestell us that ancient spa treatments startedwith an application of asphalite mud fol-lowed by a treatment of Dead Sea salt.

Imagine Cleopatra submitting to beingsmeared in muddy tar and then having thetar rubbed off her skin with bath salts.Pliny also tells us that perfume was usedto cover the smells of the pitch and salts.Boy, would Cleopatra have needed per-fume after a spa treatment like that!

PerfumesFor Cleopatra, perfumes were impor-

tant not just for masking the smells of skintreatments but to cover offensive bodyodors. Cleopatra would have carried smallcontainers of her perfumed ointments andpowdered perfumes that she would havereapplied several times a day to keep hercomplexion looking fresh and her skinsweet smelling. Remember that there wereno deodorants available in her time, and

she lived in a hot climate.Chemists have reconstructed a

number of ancient perfumes usingCleopatras own recipes and analy-sis of perfume residues found injars from Cleopatras spa. They

discovered that Cleopatra favoredperfumed ointments made from

moringa oil or horseradish oil (Moringapterygosperma or M. aptera). Those oint-ments would have disappeared into her

skin quickly and left no greasy feelingbehind. Moringa oil is still used in Persianperfumes today, and chemists at LOrealhave recreated ancient Egyptian perfumesusing moringa oil.

Other chemists have followedCleopatras ancient recipes that call formixing herbs, flower petals, leaves, orseeds with hot vegetable oil madefrom pressed olives. They letthe mixture soak for a weekat 3040C. Then, theypressed the mixture through acloth bag to extract the per-fumed oil from the pressed olivemixture. Besides using perfumesmade with olive oil to anoint herself,Cleopatra may also have added perfumedoils to her wine to give it a more pleasantsmell since those made with olive or veg-etable oils were edible.

You may have heard the saying,Flies in the ointment. It comes from avery real problem in Cleopatras spa. Flieswere ever-present in Egypt and the neareast, and they were attracted to the fatsand oils used to make perfumes. The flieswould get trapped in the perfumed oint-

Cleopatra, famous Queen of Egypt, ascended to the throne at the age of 17.She later owned a perfume factory and recorded recipes for early

cosmeticsmany used early chemical techniques.

Before you sneer at the spa treatment usingasphalite, Dead Sea mud skin care productsand bath salts are still marketed today. Infact, some of the finest spas advertise wrapsand facial masks made from mud and DeadSea salt.

Two Minneapolis students from the BreckSchool, Stacy White and Caroline Kaylor,made a project of trying to recreate ancientperfumes. They used natural materials suchas lard (as a nonpolar solvent) to extractfragrant organic molecules from rosemaryand borneal heather.

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ment and die. The ointment putrefied asthe flies decomposed, giving off a foulodor that spoiled the batch. Even the Biblemakes reference to this in Ecclesiastes10:1. Dead flies make the perfumersointment give off an evil odor . Theodor is the result of the chemical break-down of the proteins that produce dia-mines called putrescine and cadaverine.The names of these two amines areappropriatethey smell like rotting bod-ies. They can also contribute to badbreath and the less-than-desirable bodyodors that made the use of perfumes sonecessary in ancient times.

Besides perfumedessential oils, Cleopatraused powdered excrementfrom Egyptian crocodiles toclean and embellish hercomplexion. This is notas odd as it sounds.Indole, used to moderate modern-dayperfumes, is derived from feces, and urea,a component of urine, is used in modernskin-care products.

To keep her skin soft and supple,Cleopatra bathed in milk of asses, havingdiscovered an important property of pro-tein in a fatty emulsionit contains lac-tic acid that is an alpha-hydroxy acidwhich breaks down dead skin cells.Today, you can buy foaming milk baths,

and a number of modern skin-care prod-ucts contain lactic acid.

Cleopatra painted her eyes withgreen and black pigments to protect hereyes from those ever-present flies and toenhance her appearance. On spe-cial occasions, she may haveadded glitter made fromcrushed beetle shells mixedwith her eye paint. And shewould have cleaned herteeth with natron, a naturalform of baking soda, andfreshened her breath withspearmint.

When chemists used crystallo-graphic and other chemicaltests to analyze theresidues of ancient eyemakeup, they foundthat the green eyemakeup containedmalachite, which ishydrated copper(II) car-bonate (CuCO35H2O). They discoveredthat the black eye paint, called kohl, con-tained galena, a gray-lead ore of lead(II)sulfide (PbS), and cerussite, which islead(II) carbonate (PbCO3). The kohl alsocontained laurionite (PbOHCl) and phos-genite (Pb2Cl2CO3). These last twochemicals were unexpected, becausethey do not occur naturally; ancientEgyptians had to synthesize them. Fol-lowing recipes reported by Pliny,

chemists duplicated ancient methods formaking kohl by crushing PbO withnatron (Na2CO3) or rock salt (NaCl) andthen filtering the mixture and repeating

the process over the course ofseveral weeks. The rock

salt produced PbOHCl,while the carbonateresulted inPb2Cl2CO3. Mod-ern-day chemistssay these synthe-

ses developed byancient Egyptians

were the first wet-bench chemistry ever done.

Cleopatra would have dyed hernails, hands, and feet and perhaps herhair with henna from a shrub calledEgyptian privet (Lawsonia alba). Hennais a reddish-brown organic dye that wasused in Turkey as early as 7000 B.C. InCleopatras time, henna could have been

applied as a paste or by a more com-plex formulation using oil, sugar, andcitric acid. Henna is still used todayfor temporary tattoos and by a vari-ety of cultures to signify a womans

fertility.

Finally, Cleopatra would have storedher perfumed oils and cosmetics inattractive jars that were designed to holdskin care products and pigments.Archaeologists have discovered hiero-glyphs on similar jars that advertise thebenefits of using the product. Somethings just dont change!


HN

Lois Fruen teaches chemistry at the BreckSchool in Minneapolis, MN. Her articleCopper Verdigris: A Womens Art appearedin the February 2003 issue of ChemMatters.

NH2CH2CH2CH2CH2NH2 NH2CH2CH2CH2CH2CH2NH2putrescine cadaverine

indole

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The results of their project? Good if youlike fragrant lard! Stacy and Carolinesuggest that further work exploring theeffects of temperature, light, and othersolvents such as olive oil is necessary.

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By Sunday morning, it wasobvious that Ryan was quitesick. His breathing waslabored and he couldnt keep anyfood down. Patricia loaded Ryan intothe car and rushed to a local St. Louishospital. After three days of testing,doctors concluded that Ryans illnesswas due to high levels of ethyleneglycol found in his blood. Ethyleneglycol is a primary component ofautomobile antifreeze/coolant (SeeChemMatters, October 1996). Ryanwas too young to have drunk thetoxic liquid on his own someonemust have poisoned him! So, onJuly 17, 1989, the MissouriDivision of Family Ser-vices took custody ofRyan. It wasnt long before

Patricia became

the primary suspect in the poisoningof her son.

Early in September, Patricia wasgranted supervised visits duringwhich she was allowed to feed Ryan abottle. Three days after one of thesevisits, Ryan was again hospitalized.This time his condition was muchworse and doctors were unable tosave him. Ryan Stallings died on Sep-tember 7, 1989. Patricia found outabout Ryans death the next daywhen she was arrested and charged

with murder. Patriciaspent the next

sevenmonths

in jailwhileprose-

cutors builttheir case against her.

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Goes Bad!

MysteryMatters

16 ChemMatters, OCTOBER 2004

Did a mother poison herson with antifreeze?

By Tim Graham

www.chemistry.org/education/chemmatters.html

Every mothers worst

nightmare began for

Patricia Stallings on

Friday, July 7, 1989.

Her 4-month-old son,

Ryan, took his bottle

just before bedtime but

soon vomited. This set

in motion a series of

events that would for-

ever change the lives of

the Stallings family.

The mounting evidence was damning: a gal-lon of antifreeze was found in the basementof the Stallingss home, two independent labsconfirmed the presence of ethylene glycol inRyans blood serum, and postmortem analy-sis of Ryans brain tissue confirmed the pres-ence of calcium oxalate crystals, allconsistent with ethylene glycol poisoning.Patricia Stallings was convicted of 1st-degreemurder in the death of her son and sentencedto life in prison.

But heres where the story takes aninteresting twist. Three months after Ryansdeath, Patricia Stallings learned she waspregnant! Her second son, David Jr., bornfive months after Ryans death, was taken byFamily Services and placed into foster care. Afew weeks later, David Jr. experiencedseizures, vomiting, and lethargy the verysame symptoms that his brother Ryan hadsuffered previous to his death. But experts ata different hospital diagnosed David Jr. withrare metabolic disease known as methyl-malonic acidemia, or MMA, and were able totreat him. It would be this diagnosis thatwould ultimately unravel the convictionagainst Patricia Stallings.

What is MMA? Methylmalonic acidemiais an inherited illness that inhibits the bodysability to metabolize protein correctly. Mostbabies are diagnosed with the disease onlyafter they get sick. MMA results from a defi-ciency ofenzymes respon-sible for themetabolism ofmethylmalonicacid. When asufferer ofmethylmalonicacidemia eats too much pro-tein (mothers milk and babyformula are high in protein),the capacity to digest anduse the protein overloadsthe deficient enzyme sys-tem. Too little dietaryprotein triggers the bodyto break down its ownprotein, which can alsooverwhelm the enzyme.The disorder is poten-tially life threatening, but once the conditionhas been diagnosed, careful monitoring ofdiet along with a prescribed medical regimencan minimize the symptoms.

A new trialSix months after her conviction, Patricia

was granted a new trial by the state of Mis-souri. The toxicology lab at St. Louis Univer-sity provided samples of Ryans blood serumand it was determined that Ryan had also suf-fered from MMA. But would this new informa-tion be enough to exonerate PatriciaStallings? The original laboratory work hadfound ethylene glycol present in Ryans bloodserum. Since experts concluded that therecould be no mistaking any of the metabolicproducts of MMA with ethylene glycol, therewas not sufficient evidence to reverse thedecision.

Patricias case soon gained nationalexposure when it aired on an episode of theNBC television series, Unsolved Mysteries.One of the viewers of this episode was Dr.William S. Sly, a professor of Biochemistry/Molecular Biology at St. Louis University.Both Sly and a colleague, Dr. James Shoe-maker, had been following the case in thenews media. They were convinced that a com-pound called propionic acid was misidentifiedas ethylene glycol.

Was the blood testcorrect?

The laboratories that did the original ana-lytical work relied on a technique known asGC-MS. GC-MS is actually a combination oftwo technologies: the gas chromatograph andthe mass spectrometer. The gas chromato-graph is a device for separating a mixture ofcompounds according to their relative attrac-tions to a material called an adsorbent. In

chromatography, the adsorbent is known asthe stationary phase. Typically, the adsorbentis silica or alumina gel lining the columninside the machine. The sample is injectedinto a stream of carrier gas (known as themobile phase) inside the machine where itgoes through the column that is heated by anoven. The separations occur on the column.The separated compounds in the mixture passby a detector, which causes a signal to beemitted.

This signal is sent to a recorder, whichprints a chromatogram, which records the rel-ative retention times and amounts of the com-pounds present in the mixture. Afterseparation on the column in the GC, the mate-

rials then passthrough to themass spectrome-ter. In thismachine thematerials are frag-mented in thepresence of astrong magneticfield. Fragmentsof the materialsare then analyzedaccording to theirmolecular weight.The results can becompared againsta database libraryof known com-

pounds and their fragmentation patterns.The combination of information about

the physical properties of the compounds (asmeasured by its retention time) and its chemi-cal composition (as measured by its massspectrum) is extremely powerful, almost likemeasuring a fingerprint. GC-MS is practicallya gold standard for the identification ofcompounds; it is extremely rare that two dif-ferent compounds will have both the sameretention time and the same mass spectrum.For example, not only do propionic acid andethylene glycol differ in their retention time by33 seconds on a standard column, but theirmass spectra look completely different. Youwould think, as the experts testified in the sec-ond trial, that there would be no possibility ofconfusing them!

But Sly and Shoemaker were not sosure. After all, the accuracy of the resultsdepends on the technicians skill in interpret-ing the data. It is easy to deceive oneselfabout the identity of a compound present in a


HO OHC

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Methylmalonic acid

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complex mixture such as blood, particularly ifone expects to find ethylene glycol. So Sly andShoemaker applied a qualitative test thatwould give a yes-or-no answer less subject tointerpretation. One such test uses a simplecolorimetric method. Periodic acid (H5IO6)oxidizes ethylene glycol to formaldehyde,which then is reacted with a chemical calledPurpald (4-amino-3-hydrazino-5-mercapto-1,2,4-triazole). A purple-colored complexforms if ethylene glycol is present. The pair ofscientists was able to secure a sample ofRyans blood and their additional tests con-firmed their suspicions. Propionic acid,expected in the blood serum of a person suf-fering with MMA, was indeed misidentified asethylene glycol by both laboratories involvedin the original testing. Sly and Shoemakerwere so certain of their conclusions that theysent samples doped with propionic acid toseven independent commercial laboratoriesfor analysis. In fact, three of the seven labsmisidentified the propionic acid as ethyleneglycol. It would seem that few analytical labs,employing only GC-MS techniques, are capa-ble of making a reliable determination when itcomes to ethylene glycol!

Prosecutors, now a bit more uncertainabout Patricias guilt, had to take a new lookat the mounting evidence that suggested thatStallings might be innocent. They decided toconsult with a world-renowned geneticsexpert from Yale University named Dr. Piero

Rinaldo. Rinaldo agreed withSly and Shoemakers findingsand concluded that Ryanssymptoms were due to MMAand not ethylene glycol poi-soning. The original tests runon Ryans blood were alsoscrutinized and found to beinsufficient to condemn aperson to life in prison.

What aboutthe calciumoxalate crystals?

Rinaldo also concludedthat Ryans death might havebeen the result of his treat-ment for ethylene glycol poi-soning. The treatment, anethyl alcohol drip, whileappropriate for most patientssuffering from ethylene glycolpoisoning, was totally inap-propriate for a patient withMMA.

Once ethylene glycol hasentered the bloodstream, anenzyme called alcohol dehy-

drogenase (ADH) breaks it down into severalorganic acids, one of which is oxalic acid. Inan attempt to rid the body of a potentiallyharmful chemical, the enzyme makes the situ-ation worse. Oxalic acid reacts with calciumions in the blood to produce the insoluble salt,calcium oxalate. It is this substance that doesmuch of the damage to organs like the brainand kidneys.

But ethanol treatment for ethylene glycolpoisoning must be carefully monitoredbecause of the unpredictable behavior ofethanol when subjected to the human body. Insmall children, especially ones vulnerablebecause of poor health, ethanol can prove tobe just as harmful as it is helpful. Excessethanol exposure is known to increase theprecipitation of calcium oxalate resulting in acalcium deficiency in the blood (hypocal-cemia). This may well explain the crystalsfound in Ryans brain tissue post-mortem.

Faced with the new evidence collected bythe two very determined chemists, prosecu-tors for the state of Missouri dropped allcharges against Patricia Stallings. Patriciasconviction was overturned, and she wasreleased from prison 14 months after hernightmare began.

Tim Graham teaches chemistry at Roosevelt HighSchool in Wyandotte, MI. His most recent article,Scanning Electron Microscopy Solves a Mystery!,appeared in the December 2003 issue ofChemMatters.

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The mass spectra of ethylene glycol and propionic acid lookcompletely different. You would think, as the experts testified in thesecond trial, that there would be no possibility of confusing them.

Carrier gasoutlet

Detector

Manometer

Column furnace

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Recorder

Sampleapplication

Diagram of a gas chromatograph. Mixtures of compounds injected into the GC are separated by theirrelative attraction to a stationary material in the separation column. The separated (or partiallyseparated) compounds then pass through a detector, and their signal is recorded.


Shrimp ban-dages

In Iraq, Army medics are carry-ing a new bandage that canstop hemorrhaging better thanconventional gauze dressings.And its made from a familiarmenu item!

The need for a new bandageis pressing; approximately 90%of combat deaths occur before apatient gets to a hospital. Notsurprisingly, bleeding is the sin-gle most frequent cause ofdeath. But given the high technature of the modern battlefield,what is surprising is that fieldmedics have basically the sametoolsnamely, gauze dress-ingsto

stop bleeding that they had 100years ago.

That was until a group ofresearchers discovered a prop-erty of chitosana polymerderived from shrimp shells.When chitosan comes in contactwith blood, it induces clotting. Italso has antimicrobial proper-

tiessomething desirableunder dirty conditions.

How do you go fromshrimp shell to bandage? Theraw material is chitin, abiodegradable polysaccharide,similar to cellulose, found inshrimp and crab shells. Chitosanis made from chitin by removingacetyl groups (CH3-CO) from thechitin polymer chain with diluteacid. Like cellulose, chitin andchitosan are fibrous materials.By controlling the number ofacetyl groups removed along thechain or by adding new groups,chemists can tune the propertiesof chitosan to make it more ver-satile. Using a modified form ofchitosan, the researchers devel-

oped a durable and flexiblefield dressing that sticks toand seals wounds.

Could shrimp ban-dages be coming to anambulance near you? Itspossible. Traumacaused by a car acci-dent can be similar towhats seen on the bat-

tlefield. Theres no official wordon its performance, but theArmy has ordered over 50,000of the 4 4 bandages so farand awarded the manufaturer $6million to expand production. Ifthe bandages save lives, theresno doubt that paramedics willwant to start carrying them. Fornow, only the military can usethe bandages and only onextremities, but the manufac-turer of the new dressing, Hem-Con, Inc, is confident that it can

win FDA approval for a multitudeof uses.

Measuringblood sugarwith a wave ofthe arm

People with diabetes couldsoon be waving goodbye tothe pain and hassle of needles,

thanks to a new under-skin sen-sor that monitors blood sugar lev-els with a simple wave of the arm.

The research was recentlydescribed in a paper in the ACSjournal of Analytical Chemistry.

Designed as an inexpensivedevice to continually monitor theblood glucose levels of peoplewith diabetes, the passive sensorrequires no internal power supplyand no connections outside thebody. Whenever a reading isneeded, a person can wave his orher hand or arm in front of a

reader that will automaticallydetect the sensor, says CraigGrimes, lead author of the paper.

The sensor is based on"magnetoelastic" technology, thekind of technology used in plasticsecurity tags on store merchan-dise. These tags are sensed wire-lessly if someone passes atagged item through an exit.

Magnetoelastic sensors arethe magnetic equivalent of an

acoustic bell. Grimesexplains, If you hit abell with a hammer,the bell rings at acharacteristic fre-quency. If you coatthe bell with a layer ofpaint, the frequencychanges." Likewise,the molecules in amagnetoelastic sen-sor vibrate in thepresence of a mag-netic field, and thefrequency varies with

different chemical coatings.Grimes's glucose sensor is

first coated with a polymer thatresponds to changes in acidity,and then it is coated with thechemical glucose oxidase. Theglucose oxidase reacts withblood glucose to produce anacid, which causes the polymerto swell, thereby changing thefrequency of the sensor. Thereader then interprets thesechanges as blood glucose levels.

Grimes hasnt found a devel-oper to commercialize the sensor

ChemShorts

Implanted in a hand or arm, this sensor could soonmake monitoring blood sugar levels as easy aswaving your arm.

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Dont call this new 4 4 bandagea shrimp. It stops bleeding, sealswounds, and kills germs to boot!

From a news release by Jason Gorss from the ACS Office of Communications.

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Solve a mystery!Heres how you can put all thatchemistry youve been learning tousesolve a murder mystery!Download a video game that putsyou in this scene: A student diesunder mysterious circumstancesat a university reception and youare brought in to solve the crime.Using interactive menus, youinterview suspects, search forclues, and analyze evidence.Along the way, youll use yourknowledge of formula weights,stoichiometry, and the scientificmethod to solve the crime.

The Chemistry Collective atCarnegie Mellon University devel-oped the new activity with a grantfrom the National Science Foun-dation. The software is free. Todownload Mixed Reception orto get more information, visithttp://iry.chem.cmu.edu/mr/.

Bacteria batteryPhil Palko (teacher) and NikkiMcDonald (student) from IndianaSenior High School in Indiana,PA, submitted this working bat-tery in response to our challengein Bacteria Power (April 2004).You can still take on the challengeand earn your teacher a free copyof our 20-year CD. We have fourmore CDs to give away.

The battery in our articleused anaerobic soil. Since thenanother microbial fuel cell wasreported thats been popularly

referred to as using pooppower. Read about it athttp://www.newscientist.com/news/news.jsp?id=ns99994761.

Slide rules do rule!

John Brugmans class at ToutleLake High School submittedthese homemade slide rules fromthe activity we included in SlideRules Rule (April 2004). Noteasily seen is the giant slide ruleunderneath the pink slide rules.

Why was the canfloating in thecenter ofthe vaseon page 5?

The answer lies withthe small bottle to theleft of the tank. Just like dietsodas, cans of the new low-sugarsodas (like C2) float in water.Thats because the effective den-sity of the can is less than thedensity of water. Here, weveadded just enough isopropyl alco-hol (density = 0.79 g/cm3) to thesurrounding water to lower thedensity of the surrounding solu-tion. Weve created a situationknown as neutral buoyancy,where the density of the can andthe solution are the same. Its thesame condition that allows a sub-marine to stay at the same depth.

1155 Sixteenth Street, NWWashington, DC 20036-4800

Reach Us on the Web at chemistry.org/education/chemmatters.html

Chem.matters.links

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TOCQFTC/activityCarb CrazyLab on a StickQ&A Helen FreeCleopatra's SpaMystery MattersChemShortsChemMatters LinksSubscribe to CMTeacher's GuideNCW Homepage

chemmatters october 2004

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