Stanford researchers find a quicker, cheaper way to sor...(al to bring the power of isotopic analys...)

Isotopic analysis is used in a wide range of research, including geochemistry, medicine, and climatology. Until now, the analysis has been done using an isotope ratio mass spectrometer, which works by giving individual molecules an electric charge, then using a magnet to separate the isotopes by their massthe more neutrons, the more mass. One machine can cost as much as a million dollars. In addition to being expensive and large, mass spectrometers now in use require specially trained technicians to operate them.

Zare's device, which employs what is called cavity ring-down spectroscopy, has potential applications in fields as varied as medicine, geology and winemaking, he said. "Some people are willing to pay a lot of money for wine," Zare said. "You allow me to measure the isotopes, I'll tell you whether you're paying your money for the real thing or not."

Because an element's isotopes are more plentiful in certain places than in others, the ratios of different isotopes within a larger mixture act like travel diaries they can tell you the history of a mixture, whether it's from a different country, a particular part of the human body, or a previous time period. Determining the history of a mixture by measuring the ratios of its isotopes is known as isotopic analysis.

To illustrate, Zare explained that certain plants, such as corn, contain more carbon-13 than other plants. Because Americans tend to eat more corn than Europeans, isotopic analysis would detect more carbon-13 in the breath exhaled by an American than in the breath exhaled by a European, Zare said.