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Elemental


There’s a new SPA on campus. Not the snack shop, this one is a high-tech science shop for getting at the chemical subtleties behind climate change, pale- ontology, toxicology, and much more. It’s Skidmore’s Stable-isotope and Paleo- climate Analysis facility, purchased and assembled last summer. By measuring different isotopes of elements like carbon and oxygen and nitrogen, the new lab can reveal a lot about metabolic changes one meal ago or environmental condi- tions one million years ago. The SPA lab, funded by a three-year, $830,000 grant from the National Sci- ence Foundation, is run by Amy Frappier, current holder of Skidmore’s Lubin Pro- fessorship for Women in Science. Joining her in the grant is colleague Kyle Nichols. Her husband and fellow academic, Brian Frappier, is the lab manager and techni- cal guru. And it’s plenty technical—the room is a dense, intricate network of spigots and pipes, hair-thin capillaries, computers, a combustion chamber, a 700-pound magnet, tiny solid-gold sen- sors, electrical relays, vents, a dentist’s drill… Much of the peripheral equipment is for transforming a solid or liquid into a gas that can be analyzed at the core of the lab: a very sensitive and accurate stable-isotope ratio mass spectrometer.


For geoscientist Amy Frappier, a key spectrometry subject is stalagmites. Each layer of a stalagmite preserves evidence of the environment and climate during its formation. She ex- plains, “Many com- mon chem ical reac- tions, such as phase changes between liq- uid or solid or gas,


RESEARCHERS CAN GET CARBON ISOTOPES OUT OF A


FISH FOSSIL TO LEARN ABOUT ITS ENVIRONMENT AND EVEN WHETHER IT MIGRATED BETWEEN


FRESH AND SALT WATER.


cause the separation of isotopes, which are variants of an element with more or fewer neutrons and thus different molec- ular weights.” (All elements have at least a few isotopes, some radio active and some stable.) Frappier cites snowflakes: “They have different hydrogen and oxy- gen isotopes than liquid rain. Snow is still H2


electrified, so that the atoms take on a charge; the charged atoms, called ions, form a column or “ion beam,” and pass- ing it by a strong magnet makes the beam curve. The beam’s heavier and lighter ions curve at different rates, so the heavier and lighter isotopes wind up in


O, but its isotopes are lighter.” Hurri- cane rainwater, she notes, “has even lighter isotopes—finding those in a layer of stalagmite from a snow-free tropical cave suggests the layer may have grown in a stormy era.” To analyze a stalagmite in the SPA lab, Frappier and her students use a dental drill or microscraper to extract a tiny pinch of calcite powder. They dissolve the sample with acid to release its carbon and oxygen as gas, which they send into the mass spectrometer. There the gas is


AMY AND BRIAN FRAPPIER IN THEIR NEW ISOTOPE-ANALYSIS LAB


different sensor cups at the end of the flight tube’s arc. As the sensors detect their arrivals, the isotopes are recorded and displayed on a computer. Likewise a bit of hair or other tissue could be combusted and its carbon or nitrogen gas analyzed. The isotope ratio could indicate not merely the type of food eaten by the hair’s owner but the region and habitat in which that food grew. Researchers can get carbon isotopes out of a fossilized fish earbone or seashell to learn about the creature’s environ- ment and even whether it migrated be- tween fresh and salt water. Analyzing anything from soil, rock, and water to food, tissues, serum, and breath, Frappier says, “our mass spectrometer can read isotope ratios like color-coded labels to help us track myriad processes that sepa- rate or mix isotopes.”


Frappier notes that only larger uni- versities typically own such a mass spec- trometer. When she was a grad student, she sent her samples out for analysis, but “lack of machine time is a problem. The few in existence are often back- logged.” She adds that Skidmore’s new SPA lab is already helping some of her research colleagues in the UK who can’t find enough machine time to run their samples. Opening the lab at Skidmore, she says, “represents the launch of a long-term initiative to involve more students more deeply in cutting-edge research on socially relevant problems from climatology to biology, and to help train the next generations of scientists about the world of instrumentation and data collection.” —SR


WINTER 2013 SCOPE 7


GARY GOLD


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