Grant funds specialized spectrometry lab

Prof. Amy Frappier prepares a specimen
Prof. Amy Frappier prepares a specimen, while
lab manager Brian Frappier observes
(more photos below)

Rocks, shells, hair, even breath can yield new data about climate, ocean chemistry, metabolism, and more, thanks to Skidmore’s isotope mass spectrometer.

November 8, 2012

Skidmore has a new, high-tech laboratory for getting at the chemical subtleties behind climate change, paleontology, toxicology, and much more. The Stable-isotope and Paleoclimate Analysis facility, called the SPA lab for short, was purchased and assembled last summer. By measuring different isotopes of elements like carbon and oxygen and nitrogen, it can reveal a lot about metabolic changes one meal ago or environmental conditions a million years ago.

Funded by a three-year, $830,000 grant from the National Science Foundation, the lab is run by Amy Frappier, current holder of Skidmore’s Lubin Professorship 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 technical 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 sensors, 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 Frappier, a key spectrometry subject is stalagmites. Each layer of a stalagmite preserves evidence of the environment and climate during its formation. Frappier explains, “Many common chemical reactions, such as phase changes between liquid or solid or gas, cause the separation of isotopes, which are variants of an element with more or fewer neutrons and thus different molecular weights.” (All elements have at least a few isotopes, some radioactive and some stable.) Frappier cites snowflakes: “They have different hydrogen and oxygen isotopes than liquid raindrops. Snow is still H2O, but its isotopes are lighter.” Hurricane 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 electrified, so that the atoms take on a charge; charged atoms, called ions, form a column or “ion beam,” and passing 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 end up in 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 fish earbone or a seashell to learn about the creature’s environment and even whether it migrated between 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 separate or mix isotopes.”

Frappier notes that only larger universities typically own such a mass spectrometer. 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 backlogged.” 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.”

(Photos by Gary Gold)