Follow an analytical chemist who protects horses – a STEM career glimpse and puzzle

Horses thunder past, stretch across the finish line. The fastest one wins by a nose. Victory brings fame and fortune to the owner.

And this victory is the end result of generations of expert horsemen and horsewomen breeding generations of extraordinary horses, and of the horse’s years of hard work with fine trainers, so that the best may win on race day. At least that’s the way it should be.

Unfortunately, money is at stake, so that some people cheat to help a horse they own, or train, win races. One kind of cheating is doping by giving drugs to horses to make them run faster.

Some people give shots of blood booster drugs to horses. More red blood cells carry more oxygen to all tissues in the horse’s body, including muscles. Instead of getting tired in the last stretch, the horse can keep going full tilt. But this is cheating, therefore it is is prohibited.

How can one catch cheaters? By testing the horse for prohibited drugs: blood and urine samples are collected after races.

Lab scientists test the samples for prohibited drugs. If the scientists find one, the people responsible for that horse have broken the rules and must be punished.

But what happens when a new drug becomes available? For example, by 2008, a new and improved blood booster medicine, CERA, had become available. CERA was invented to treat humans who have serious medical problems, not to help healthy athletes or horses cheat!

Researchers in Europe invented a test to look for CERA in athletes’ samples. Sadly, they found CERA in athletes' samples, including from 2008 Tour de France and Beijing Olympics cyclists.

Fortunately for horses everywhere, Dr. Yan Chang was already working hard to fine tune a test to find CERA in horses’ samples. If there is a test, cheaters might get caught, so they will think twice before giving a horse a shot, and hopefully they will forget it.

Dr. Yan Chang

How exactly does Yan’s test work to confirm that CERA was present in a horse’s sample?

She spends three days just preparing the samples. She treats them in a special way that cuts the CERA molecules, if they’re there, into pieces. One of those pieces, “T6,” can only come from CERA, nothing else. So finding T6 proves that CERA was there. To see whether T6 was there, Yan analyzes her samples by chromatography and mass spectrometry.

Yan uses chromatography and mass spectrometry

to test horse samples for a prohibited drug

Chromatography separates the ingredients of a mixture. The mixture goes into the machine, and the ingredients come out one by one at the other end. In the example below, chromatography has separated the two ingredients in a mixture:

Yan uses chromatography to separate T6 from all the other things in the horse’s blood. Then she uses mass spectrometry to identify T6.

For an explanation of how chromatography and mass spectrometry help identify chemicals, watch my TV science lesson (part 1 – from 3:30 minutes to the end at 10 minutes) by clicking here.

How exactly does Yan read what she gets from a test—the data?

Yan reads data

First of all, she always compares the unknown sample to known samples (controls): one control known to be negative (-) (because it’s blood from a research horse who was never given CERA) and one control known to be positive (+) (because Yan herself sprinkled CERA into horse blood in a test tube).

(In my TV science lesson, I omitted the negative control for the sake of simplification, to make room for other details.)

Yan’s data look like this:

- In the picture below, for the positive control (+), Yan knows that T6 is present, and sure enough, there are two peaks. The two peaks line up on the same vertical. The top peak is bigger than the bottom peak. The top peak is three times bigger than the bottom peak. That’s what the data look like when T6 is present.

- In the next picture, for the negative control (-), Yan knows that T6 is absent, and sure enough, there is no peak.

- Yan now looks at the unknown data (?) in the picture below, and asks three questions.

- Question 1: are there peaks?

            - If not, the sample is negative

            - If yes, Yan goes on.

- Question 2: are the top and bottom peaks lined up with each other on the same vertical as the positive control?

            - If not, the sample is negative

            - If yes, Yan goes on.

- Question 3: is the top peak three times bigger than the bottom peak, like for the positive control?

            - If not, the sample is negative

            - If yes, the sample is positive for T6.

That’s the big idea, although it was simplified to avoid giving you a headache.

Now it’s your turn to be a horse-race detective. Ask Questions 1, 2, and 3 about samples A-I below. Decide which horse was doped with CERA.

A: Attahorse

B: Beeg

C: Catch Me Tomorrow

D: Desert Wind

E: Egg Beater

F: Flies Like An Arrow

G: Girl Power

  

H: His Goofiness

I: Itching To Run

Click here for the answers.

Yan and her teammates published the test recipe in a science journal so other lab scientists can do it too. This protects race horses from being doped with CERA.

A NOTE ABOUT MATCHING PICTURES
If you take pictures of your cat, ten in a row, you don’t expect all of them to be identical. Yet anyone can tell that it’s the same cat—there’s a match! Scientists look at data the same way: to identify a drug, the unknown and the positive control don’t have to be identical, but they have to match well enough.

ABOUT YAN CHANG

• Yan has earned a Bachelor of Science (B.S.) degree in Chemistry from Shanxi University (Taiyuan, People's Republic of China or PRC) and a doctoral degree (Ph.D.) from the Chinese Academy of Medical Sciences (Beijing, PRC).

• She now lives in California.

• When she's not working, she loves to spend time with her young daughter playing puzzles and reading. She also loves to cook.

LINKS & MORE

• The reference for Yan’s publication in a science journal is

Y. Chang, G. M. Maylin, G. Matsumoto, S. M. Neades and D. H. Catlin. Screen and confirmation of PEG-epoetin β in equine plasma, Drug Testing and Analysis, 2011, 3:68–73.

Disclaimer: the substance of this publication was greatly simplified in order to adapt it for the above blog post.

• Go behind the scenes at a British race track. See how an official collects a sample from a horse, in the video at this web page.


• For an overview of chemistry careers, click on “Podcast" at the Sloan Career Cornerstone Center. It’s an introduction to the required schooling, a day-in-the-life of a chemist, jobs, and more.

• Read a paragraph-long description of analytical chemistry

• Read a paragraph-long description of forensic chemistry (analyzing evidence of a crime), or a two-page-long description of forensic chemistry

• Read an overview of Forensic Science Technician careers at ScienceBuddies.org.

• This info-packed web page by the American Chemical Society contains descriptions of eight different analytical chemists’ jobs, in the following specialties:

- Forensic Pharmaceutical Analysis
- Product Marketing
- Entrepreneur: Analytical Chemistry
- Entrepreneur: Analytical Chemistry Systems Integration
- Bioanalytical-Related Chemistry
- Environmental Analysis
- Chemometrics/Fish Products and Food Quality

Updated January 31, 2012