Few places are as hot as 6,000 degrees Centigrade: the surface of the sun, the center of the Earth, the heart of a laboratory device at Oregon State University. In the lab, this is the temperature of a kind of flame produced when argon gas flows through an intense electromagnetic field. Appropriately, the part of the device that holds the flowing gas is called a “torch.” As the gas ionizes — as it separates into positively and negatively charged particles — it becomes neither liquid nor solid nor gas. It becomes plasma, the fourth state of matter.
Welcome to the W. M. Keck Collaboratory for Plasma Spectrometry. Researchers from as far away as Estonia and as close as down the hall use the lab’s analytical equipment — known in scientific jargon as an inductively coupled plasma mass spectrometer, or ICP-MS — to answer a variety of stubborn questions: Why do nerve cells die in the course of Lou Gehrig’s disease? What causes volcanoes to erupt? How does the Earth’s climate system operate? Where do fish spend their time as they navigate watersheds and the oceans?
The ICP-MS enables scientists to look for clues in the amounts and proportions of elements that are contained in river water, fish bones, ice cores, nanomaterials and cell cultures. With exquisite precision, the Keck Collaboratory identifies elements both rare (strontium, hafnium) and common (calcium, magnesium, copper) and enables scientists to find chemical patterns — what you might call elemental fingerprints — that point to answers.
DIY Science
As its name implies, the lab is about scientists working together. “We’re not a service lab,” says manager Andy Ungerer, who came to Oregon State in 1973 to do a master’s degree with nuclear chemist Walter Loveland. “There are places where you can send samples, and they’ll send back a spreadsheet. From the beginning, we’ve felt it is important for users to learn as much about the equipment as they could. You can only do that by running the samples yourself.”
Ungerer and Gary Klinkhammer, emeritus professor and Keck lab founder, took this DIY approach when they received funding from the National Science Foundation (NSF) to install their first ICP-MS in 1992. With grants from the Keck Foundation in 2000 and from the NSF in 2011, the lab added more powerful mass spectrometers, the machines that separate and measure elements.
The analytical process can start when a liquid sample is sprayed into the torch. Or it can begin with a solid material, such as the fish otolith or rock crystal above. Scientists fire a laser beam at the material, and the collision sends molecules into the torch on a current of helium gas.
As molecules break apart in the plasma, the elements that comprise them are extracted and sent into a mass spectrometer that separates them by mass and ionic charge. Another device, an emission spectrometer, can add additional data based on the light emitted by the elements.
Plasma spectrometry is so sensitive that it can find one atom in a trillion — the equivalent of a drop of water in an Olympic swimming pool.
Over the last four years, more than 120 scientists and 50 Oregon State graduate students have used the lab for their research.
