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EMSL follows user's instruments into atmosphere

Think Global, Act Nano

First, move across the world and help invent a machine that, in turn, reinvents what people know about the smallest-scale particles. Then, augment a research area that cuts across scientific disciplines and societal applications (nanoparticle studies) to find new ways to collect multiple types of data. At the same time. In one machine.

And when you’re finished with that, redesign your machine to fit perfectly into an airplane and fly it through ice clouds at the North Slope of Alaska—and many other places around the world—to collect real-time data on atmospheric aerosol particles and their effects on climate change.

Frequent Flyer

Sound doable? Not for most.

But for EMSL user Alla Zelenyuk—in collaboration with colleagues and through the use of key resources at EMSL—it’s all in a few years’ work.

In the case of “SPLAT II,” a one-of-a-kind, field-deployable single particle mass spectrometer, the instrument/person connection is unmistakable. The story of Zelenyuk and SPLAT is one of parallel development, of expansive thinking and of intricate measurements.

Curious play to serious physics

Zelenyuk grew up in Ukraine, the daughter of secondary physics and math teachers. She remembers the early exposure to science her parents enabled.

“Instead of the regular day-care toys, I played with lenses and magnets,” she says.

Soon, the curiosity of play translated into more serious endeavors: at age 11, she began to enter, and win, physics competitions. Fast forward a decade or so to the famed Moscow Institute of Physics and Technology. After Zelenyuk earned a PhD through the Institute of Chemical Physics, the question became where to continue her career.

“Because of the recent collapse of the Soviet Union, it became increasingly difficult for scientists to find jobs—to survive in general. More and more graduates, myself included, relocated to the U.S. after defending their PhD theses.”

In the United States, she found the up-and-coming field of aerosol particle characterization waiting for her. But things started small. Very small.

As a postdoctoral fellow at the University of North Carolina, she worked with Professor Tomas Baer on early efforts in single particle mass spectrometry.

“With little funding—and no experience with lasers or aerosols—we began new projects in a very new field,” she says.

An adult version of her former “playing with magnets and lenses,” Zelenyuk quenched her curiosity about lasers and aerosols at UNC. These projects led to a postdoctoral fellowship at the Department of Energy’s Brookhaven National Laboratory, where she worked with colleagues to invent the first SPLAT (Single Particle Laser Ablation Time-of-Flight) mass spectrometer.

“In the beginning with SPLAT, we realized that aerosol particles are ubiquitous across science applications,” she remembers. “And that the characteristics and relationships of individual particles will reveal their ultimate impact.”

This recognition, that single aerosol particles deeply affect disparate systems (human lungs; engine exhaust, performance, and pollution; and the earth’s atmosphere and climate to name a few) informed her scientific work. Basically, improving her field meant taking more accurate measurements of these important particles one at a time to understand them better. Unsatisfied with the initial lower size limits, and confinement to the basic measurements of size and composition, Zelenyuk began to push the boundaries.

Beyond boundaries

After serving as a staff scientist at Brookhaven, Zelenyuk made the move in 2003 to Pacific Northwest National Laboratory. She quickly made use of EMSL— DOE’s national user facility at PNNL— with the invention of SPLAT II and its construction in EMSL’s machine shop and Instrument Development Laboratory. SPLAT II provides a platform that can continually be improved—allowing the aforementioned boundaries to be broken.

“Our goal was to improve on the basics [nanoparticle size and composition], but also add characteristics to the list of measurements SPLAT conducts—to connect the dots in one instrument rather than using multiple instruments.”

It worked.

Frequent Flyer

Today, SPLAT II simultaneously measures the number, concentration, size, composition, density, shape, morphology, fractal dimension, and hygroscopic properties of individual particles as small as 50 nm in diameter. This multi-dimensional particle characterization doesn’t just happen in the lab, either. At EMSL, Zelenyuk and others recognized the need to measure these particles in their natural environment, and responded accordingly.

After a redesign, SPLAT II can now yield quantitative information on particle physical and chemical properties in the laboratory or in the field—even aboard an aircraft.

Even after adding to SPLAT’s range of data and finding new ways to collect them, Zelenyuk isn’t satisfied.

“Now we’re figuring out what to do with all this data—to explore large, multi-dimensional data sets without loss of information, and zoom in on the ‘golden nuggets’ [the most relevant results] within.”

This piece of the puzzle was provided by working closely with Professor Klaus Muller from SUNY Stony Brook, a computer science researcher. The results are SpectraMiner and ClusterSculptor, a suite of companion software developed specifically to handle the vast amount of data SPLAT collects.

Zelenyuk explains how SPLAT’s access to diverse, usable data allows scientists to not only measure the features of nanoparticles, but also study the interactions and relationships between them. For these reasons, SPLAT has been used around the world, and is consistently in high demand across a variety of projects. Of course, this works well with Zelenyuk’s inherent curiosity.

“It’s exciting to me to learn new things in distant scientific fields. Currently, SPLAT is being used in a partnership [with the University of Wisconsin] related to the development of new engines and biofuels, both in modeling engine performance and characterizing the composition of emissions.”

It’s no wonder EMSL’s world-class instruments consistently overlap with its staff expertise. For Zelenyuk, her career in science and SPLAT itself are uniquely interwoven.

“You don’t know how many times I’ve been called ‘the SPLAT lady’,” she jokes. “When we began putting the instrument on airplanes, the name made some people uneasy... but I assured them: the only things that go splat are the particles.”

Aside from the nickname connection, the instrument reflects the scientist in two key characteristics they share: the thirst for vast and varied knowledge, and the application of special capabilities to important problems—one very small piece at a time.

EMSL Instruments Take to the Skies for CARES

During a month-long field campaign in California’s Sacramento Valley, several EMSL instruments are hard at work—aboard aircraft and on the ground—examining the intricacies of how aerosol particles affect the climate. EMSL’s Time-Resolved Aerosol Collector (TRAC2), DRUM Sampler, and Single Particle Laser Ablation Time-of-Flight Mass Spectrometer (SPLAT II) are contributing to the Carbonaceous Aerosols and Radiative Effects Study (CARES). The study is a collaboration of over sixty scientists hailing from a dozen institutions, including EMSL, Pacific Northwest National Laboratory and other national laboratories, several universities, and other government entities like NASA. A massive effort to collect vital aerosol data to help scientists improve climate models, CARES is coordinated through the U.S. Department of Energy’s (DOE's) Atmospheric Radiation Measurement (ARM) Climate Research Facility. Like EMSL, ARM is a national scientific user facility supported by DOE’s Office of Biological and Environmental Research.

SPLAT II is available for free-of-charge use through a peer-reviewed user proposal process at the Environmental Molecular Science Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research. The instrument has been involved in several scientific discoveries and high-profile publications, including invited papers in the Proceedings of the National Academy of Sciences and the International Review of Physical Chemistry, as well as a very highly cited article in Aerosol Science and Technology.

Find the latest SPLAT-related publications here: http://www.emsl.pnl.gov/capabilities/viewInstrument.jsp?id=34020.

Released: July 13, 2010