UNIVERSITY PARK, Pa. -- A mass spectrometer that gives researchers the ability to measure isotopic composition to less than one-hundredth of a percent precision is up and running on campus, offering the ability to study isotope systems previously inaccessible at Penn State.
The equipment, a Thermo Scientific Neptune Plus purchased in 2011 with a $724,000 National Science Foundation MRI grant, allows researchers to study the isotopic composition of elements to a more refined level than before. Matthew Fantle, assistant professor of geosciences and the principal investigator on the grant, said the equipment is operated under the auspices of Penn State Institutes for Energy and the Environment and LIME (Laboratory for Isotopes and Metals in the Environment) and is available to faculty and students across the Penn State campus.
The multiple collector inductively coupled mass spectrometer is housed in the Metal Isotope Laboratory (MIL), a clean laboratory on the ground floor of Hosler Building. Protocol have been developed for measuring the isotopic compositions of lithium, magnesium, calcium, iron, strontium and copper, and capabilities exist to measure elements such as silicon, nickel, cadmium and zinc. The spectrometer, the only one of its kind on campus, is unique in that it is capable of determining the isotopic composition of so-called “non-traditional” elements that are not measureable using other means.
Because samples are introduced in acidic solutions, a dust-free clean lab is integral to the successful operation of the instrument. Before entering the facility, researchers and visitors must step onto a sticky pad to trap stray debris brought in on their shoes, then change into clean rubber clogs available in the entry room.
The entry area, Fantle explained, serves as a buffer to help keep contaminants out of the lab. A HEPA filtered air system also helps keep the environment clean – the lab is kept under positive air pressure that pushes air out of the main labs and into the entry way. The rooms contain no metal, which can corrode over time and introduce unwanted contaminants. Instead, most of the equipment and lab supplies are Teflon and plastic.
The lab includes what are known as Class 10,000 facilities, in which natural samples are dissolved in acidic solutions, and a Class 1,000 space, in which dissolved samples are chromatigraphically purified. Those spaces are “clean rooms” because of the relatively low number of air particles. The goal of the preparation work is to create as pure a solution as possible, which can then be introduced into the mass spectrometer and measured at high precision.
The field of “non-traditional” isotopes is relatively new, but its use is growing rapidly in the geosciences. The mass spectrometer may be useful, for example, to a material scientist interested in the mechanism by which a solid forms or in a precise mass balance of unwanted impurities without analyzing the entire solid, Fantle said. Environmental scientists might use the isotope systems measured by the MC-ICP-MS to fingerprint various contaminants in a natural system such as Marcellus Shale production waters and/or acid mine drainage.
“There’s power in the ability to see these small differences,” said Fantle, an associate in Penn State’s Earth and Environmental Systems Institute.
“Isotopes provide a way to track what’s happening in a system,” he said, “especially in cases where the processes are too small to observe.”
For more information about the mass spectrometer, clean facility and contact information, visit http://www.eesi.psu.edu/LIME/Home/Welcome.html