Nature's Fingerprints

Millions of different kinds of atoms and molecules make up everything in the world, including you. Sometimes it’s important to know what kind of atoms or molecules are in a suspicious package or a person’s breath. Some molecules like carbon dioxide are found in everybody’s breath, but other molecules only show up in your breath if you smoke cigarettes or something in your body like your kidneys isn’t working right. The molecules in your breath are like fingerprints: they are a little different for each person.

There are more than a thousand molecules that can show up in people’s breath, and doctors are very interested in a new breath analyzer that was invented in scientist Jun Ye’s lab at JILA. This breath analyzer can identify hundreds of different things found in breath. It’s a quick and easy way to help doctors check your health. Right now, doctors at the University of Colorado Health Sciences Center are studying the new breath analyzer to see how well it works with their patients.

Being able to quickly identify atoms and molecules is also important when someone finds a suspicious package.  Dr. Ye says that the same technique used for breath analysis can also identify the molecular fingerprints of atoms and molecules in tiny amounts of gas given off by a mysterious package. This new technique can even measure the amounts of different greenhouse gases in the atmosphere. Molecular fingerprinting is a very exciting new way of solving mysteries in nature.

Molecular fingerprinting uses lasers that emit hundreds of different colors. Each atom or molecule soaks up only some of the colors, creating a one-of-a-kind fingerprint that makes it possible to identify exactly what it is and how much of it is present. Since different atoms and molecules soak up different sets of colors, their fingerprints are distinctive enough that scientists can identify every one of them in a mixture.  Plus, the identification process is quick and easy.

The picture shows different molecules absorbing unique sets of colors (molecular fingerprints) from laser light.  The molecular fingerprints made in this way can help doctors analyze breath, computer chip manufacturers test for unwanted molecules called impurities in the gas used to grow the chips, and climate scientists understand earth’s atmosphere. - Julie Phillips