Health Sciences


The Chemical Safety Board: Useful Information and Great Videos

September 11, 2013

The U.S. Chemical Safety Board (CSB) is a federal government agency which has a mandate to investigate chemical accidents. Unfortunately, the CSB has no shortage of work, since there is apparently an endless supply of such accidents in the U.S. (and elsewhere, of course). The good news is that often these incidents provide valuable insights into safety issues and can serve as useful learning tools. The CSB has done a great job of investigating a wide variety of workplace accidents, from small to large scale, and producing very high quality videos which provide unique insights into the causes of these accidents. In my Laboratory Safety course, I often use these videos to highlight a range of safety concerns and encourage my students to identify the root causes of the incidents and determine what could have been done differently.

An image from a CSB video.

An image from a CSB video.

Anyone with an interest in chemical or industrial safety might want to spend some time on the CSB website, especially on the video section, which currently hosts about 50 videos on subjects as diverse as reactive hazards, static electrical discharge and combustible dusts. – Michael Judge.


Chemical of the Week: Aspartame

August 30, 2013

Aspartame is the commonly used name for the artificial sweetener N-(L-α-aspartyl)-L-phenylalanine, 1-methyl ester. It was discovered when a chemist working in the Searle labs in 1965 accidentally ingested some and realized it tasted sweet. The chemist at the time was working on drugs to control ulcers! It is formed by making the dipeptide of two amino acids and then producing the methyl ester of that molecule.

The aspartame molecule.

The aspartame molecule.

It is about 200 times sweeter than sugar and so can sweeten foods without adding a lot of calories, since little is required. Aspartame is very widely used today for numerous foods and beverages, although not without controversy.  For decades, there have been concerns and even conspiracy theories associated with the use of aspartame, and it has been claimed to cause numerous health problems ranging from simple headaches to cancer. Many studies over several decades, however, have consistently shown that aspartame is safe at normal levels of ingestion and it continues to be approved for use by the FDA, the EU and other worldwide regulatory agencies.

Chemical of the Week: Heroin

August 18, 2013

Heroin is a member of the alkaloid family of chemicals (which normally contain a somewhat basic nitrogen group). It is produced by chemical modification of morphine; the principal opiate obtained from the poppy plant. The synthesis of heroin from morphine is actually fairly simple and involves the acetylation of two hydroxyl groups, hence heroin is also known as diacetylmorphine.

The heroin molecule. Note the two acetyl groups on the left.

The heroin molecule. Note the two acetyl groups on the left.

Heroin was synthesized and produced commercially in the late 19th century by the Bayer company in Germany and was intended to be a non-addictive substitute for morphine, which was a common medical ingredient at the time. The name “heroin” was meant to reflect the chemical’s heroic properties (an early attempt at branding!). As we all know, this idea didn’t work out so well, since heroin is actually extremely addictive. In fact, heroin is about twice as powerful as morphine, possibly because it is less polar and can more readily move into the brain once it enters the body. The dangers of heroin were quickly recognized and it was banned quite soon after it became available (in 1924 in the U.S., for example).

Chemical of the Week: Californium

August 12, 2013

With the warm weather still here, Californium is a good choice for the element of the week! This element was first created in the labs of the University of California, Berkeley in 1950 and is named after the balmy State of California. That was in the good old days when, if you made it, you got to name it! Californium is produced by bombarding other elements (such as curium) with subatomic particles.

U of California researchers work with Californium in the ‘60s. Note the snappy attire!

U of California researchers work with Californium in the ‘60s. Note the snappy attire!

The 252 isotope of this element is a very powerful radioisotope, emitting millions of neutrons per second. It has several practical applications, such as providing the initial radiation input for the start-up of nuclear reactors.

Californium has the distinction of being perhaps the most expensive commodity chemical on earth. The price in 1999 was $60 per microgram, or $60,000,000 per gram, which is about two million times more expensive than gold.

Chemical of the Week: Kevlar

August 1, 2013

Kevlar is the DuPont brand name for an aramid (aromatic amide) polymer first developed in 1965. The para orientation of the benzene substituents in the repeating unit allows a high degree of hydrogen bonding between polymer chains in this material. As a result, the polymer in the solid phase forms rod-like liquid crystal packing structures. Spun fibers of this material are exceptionally strong; Kevlar has about eight times the strength of steel on a per-weight basis.

The molecular structure of Kevlar.

The molecular structure of Kevlar.

The synthesis and processing of Kevlar is difficult, since a solution of concentrated sulfuric acid is required to dissolve the polymer, and consequently the price for this polymer is quite high. Nevertheless, it’s unique combination of strength, low density and flexibility have led to numerous applications, including body armour, bridge cables and the roof of Montreal’s Olympic stadium.

Free Textbooks!

July 28, 2013

Every college student knows that the cost of textbooks can be exceedingly high. For a short but interesting discussion of this topic, check out this article. As you can see from the attached graphic (taken from the linked article), the cost of textbooks has risen much faster than the consumer price index (aka inflation). There are various reasons put forward to explain this, but whatever the cause the end result is that students are left paying very high prices which they often can’t afford.

Rising textbooks costs (see linked article for source).

Rising textbooks costs (see linked article for source).

What can you do about this as a student? There are a number of creative options which you can try with varying degrees of success, including obvious ones like buying second hand books. Another option, though, is to use a free book. More and more textbooks are showing up on the internet as freely distributed materials. Of course, some of these are pirated and illegally uploaded (and downloaded!) but many are specifically written and/or posted online as free.

In preparation for my upcoming statistics course, I did some looking around on the internet and found a site called OpenIntro. This organization was founded by a Harvard professor and a Google analyst with the aim of providing free, open source textbooks to students. It sounds too good to be true, but the site really does provide high quality educational texts free of charge, written specifically for OpenIntro. At the moment, the only free textbook is on statistics, but it is a well written, 400 page text authored by professors from Harvard and Duke universities, complete with graphics and problem sets. I currently use this book as the main textbook for my statistics course within the chemical and biosciences coop program. It can be downloaded free of charge as a PDF at the OpenIntro website. I recommend that anyone with an interest in stats have a look at the site and see what they think of the book. We can only hope that free open source textbooks are the way of the future! – Michael Judge.

Chemical of the Week: Tetrodotoxin

July 23, 2013

Tetrodotoxin (TTX) is a very powerful nerve toxin found in the puffer fish and some other marine animals such as starfish.

TTX works by interfering with the ability of nerve membranes to transport sodium. Ingestion of small amounts of TTX produces a feeling of numbness in the face along with a floating sensation. Larger amounts can produce paralysis and death, although “large” is relative here, since less than a milligram can be fatal.

The tetrodotoxin molecule.

The tetrodotoxin molecule.

Puffer fish (or “fugu”) is considered a delicacy in Japan and even though only carefully trained chefs are allowed to prepare it, 179 deaths were reported in a ten year period due to eating fugu. Interestingly, TTX has been proposed by one anthropologist as an ingredient in the potions of voodoo practitioners in Haiti. The theory is that a victim is given TTX and slips into a paralytic coma indistinguishable from death, only to be revived later as the living dead, or a zombie! Fans of the Simpsons will remember that Homer once believed he was suffering from fugu poisoning.

Course FAQ: Organic Chemistry

July 21, 2013

Q. Just what exactly is organic chemistry?

A. In the early days of chemistry, scientists found they could extract interesting compounds from substances sourced from living systems, such as butter, animal fat and so on. For this reason, these isolated chemicals generally became known as “organic.”. Today, organic chemistry is more generally considered to be the study of chemicals which are primarily based on carbon (although there are a few exceptions, such as carbon dioxide, which is not considered organic). The vast majority of chemicals are organic by this definition, including vitamins, proteins, pesticides, plastics and many others.

Organic chemistry involves understanding the structures and names of these compounds as well as how they react and how they are synthesized.

Cadbury's creme eggs. How do they get that yolk such a bright yellow?

Cadbury’s creme eggs. How do they get that yolk such a bright yellow?

Q. Why do we study organic chemistry?

A. In many ways, organic chemistry is the gateway to the study of many other sciences, including biochemistry and biology. A good knowledge of the basics of organic chemistry lets you understand how living systems function, since biological systems are mostly made of organic compounds.

In addition, many industrial processes are essentially organic chemistry. The paint and coating, nutraceutical and pharmaceutical industries all involve organic reactions, for example.

As well, some knowledge of organic chemistry is also useful in just about any field of science for practical reasons. A lot of organic compounds are used as solvents, for example, so its helpful to know the difference between ethanol, methanol and isopropanol.

Q. What do we learn in the lectures?

A. All kinds of things! We begin with a brief study of how organic molecules are put together, by talking about bonding and electron structures. We then learn how to name organic compounds using the formal naming system devised by IUPAC.

As well, we learn about the most common reactions of organic chemicals. We’ll discuss how some everyday organic compounds are made, such as polyethylene, aspirin and 2,4-D.

The fascinating effects of isomerism are also considered. Isomers are chemicals which have the same atoms but different properties depending on how the atoms are put together. For a good intro to isomerism, check out this video.

Finally, the course also teaches the theory and practice of some common lab techniques, such as distillation.

Q. What about labs?

A. There are five to six lab sessions in each of the two organic chemistry courses. In these labs, you will apply the theory and see the results in action. Experiments include synthesizing interesting chemicals, such as a bright red dye (an azo dye: see the photo above and the note below!). You will also learn many standard organic lab techniques, such as distillation, recrystallization and melting point analysis. If you ever wanted to start making moonshine whiskey in your backyard shed, this is your starting point! (just kidding, please don’t start making moonshine in your shed.)

Q. Is it tough?

A. Organic chemistry can be challenging, but it’s doable! The subject matter is not extremely difficult, but it requires dedication and good study habits since there is a bit of memorization required in some places to be able to use the nomenclature system and also to recall the various reactions. However, if you can remember that positive and negative charges attract each other, you have just conquered about half of organic chemistry.

Note: the image shows Cadbury’s Easter Creme Eggs, which were recently involved in a scandal when the treat was found to contain an azo dye after the company had promised to remove it.

Interesting News from the World of Science: A Safer Painkiller?

July 17, 2013

The active ingredient in Tylenol and many other painkillers is a drug known as acetaminophen (or sometimes paracetamol). Acetaminophen has been around for a long time and works pretty well, but it’s well known that this particular drug is highly toxic to the liver when taken in overdose or when the patient’s liver function is already compromised (this is why you do NOT take Tylenol for a hangover!). In the U.S., for example, acetaminophen is believed to be responsible for about half of all cases of acute liver failure.

Acetaminophen (top) and new potential replacements (bottom).

Acetaminophen (top) and new potential replacements (bottom).

The liver toxicity occurs because liver enzymes metabolize the drug into a harmful compound known as an iminoquinone. This metabolization has nothing to do with the pain killing function of acetaminophen and so a drug which is not metabolized in this way but still works to reduce pain would be beneficial.

A recent publication in ACS Medicinal Chemistry Letters details preliminary attempts to synthesize analogues of acetaminophen which still work like acetaminophen but don’t generate toxic metabolites. These are based on tweaking the acetaminophen structure to add two heterocycles in place of the single benzene ring in the original structure.

The new drugs are still in the preliminary stages and it’s not yet known if they will work. There is a precedent, however, the even more popular painkiller ASA (i.e. Aspirin) is based on tweaking the structure of an older drug.


Chemical of the Week: 2,4-D (The enemy of dandelions everywhere!)

July 16, 2013

2,4-dichlorophenoxyacetic acid (2,4-D) is a widely used synthetic herbicide. It affects only “broadleaf” plants (typically the plants we consider weeds) and not grasses or most crops, hence it can be widely applied without harming desirable vegetation. This chemical mimics natural plant hormones and causes rapid, uncontrolled growth of broadleaves, leading to death of the plant. Pure 2,4-D is actually relatively insoluble in water and so other forms, such as esters and salts, are now more widely used.

The 2,4-D structure.

The 2,4-D structure.

2,4-D is applied so commonly that a 2003 study found that 63% of homes contained traces of this chemical in household dust! It was also a component of the infamous Agent Orange herbicide used during the Vietnam War. Exposure of military personnel to Agent Orange was subsequently connected to a wide variety of health problems. Currently, it is believed that these health issues were actually more likely due to the presence of other chemicals present in Agent Orange, such as traces of dioxin.