In-field chemistry everywhere with handheld LIBS

August 31, 2021

Russell Harmon: A vision for the future of LIBS

SciAps debuted the world’s first truly portable handheld only a few years ago, but Dr. Russell Harmon, a geochemist who has been working with laboratory LIBS for more than 20 years, says the real-time, rapid analysis capabilities of SciAps Z-series sets a new standard for chemical analysis in the field. His new mission is to spread the word. To find out how SciAps became the world's favorite handheld, read "Handheld LIBS—the latest success story in portable analytical instrumentation."

Russell Harmon, Ph.D., adjunct associate professor, Department of Marine, Earth, & Atmospheric Sciences, North Carolina State University

The Holy Grail for geology

Russell Harmon’s work in laboratory LIBS ranges from detecting lead in paint and soil, to explosives detection and analysis of landmine casings at the U. S. Army Research Laboratory, to working with partners like Dr. Richard Hark on applying the concept of “geochemical fingerprinting” to conflict minerals to determine where they were mined.

Earlier in his career, he spent ten years studying volcanoes in the Andes. During that time, hundreds of samples were collected in lava flow sequences and transported back to the laboratory for analysis by expensive and time-consuming techniques in order to find the few chemically distinct samples of importance. “To have an analyzer that could tell us that in the field, so that we only had to bring back ten instead of hundreds of samples, would have been wonderful,” says Harmon.

“So when I began to work with laboratory LIBS, I knew that this could be the ‘Holy Grail’ for geochemical analysis in the field once brought into a handheld form, as had recently happened with XRF,” says Harmon.

Geochemical fingerprinting in seconds

In the mid-2010s, with a truly portable handheld LIBS on the horizon, Dr. Harmon began using laboratory LIBS to illustrate the potential of fingerprinting for the geological community.

“I saw that field portable XRF units were just starting to hit the market and knew that handheld LIBS technology had to come of age, sooner or later, for geology,” says Harmon.

By 2010, the interest in miniaturizing the LIBS components grew, leading to spark OES and “LIBS in a box” — basically a suitcase full of instrumentation carried into the field — until in 2015, SciAps developed the first handheld LIBS, the Z-500. Suddenly and conclusively, he and his colleagues could demonstrate the application of handheld LIBS in situ. Harmon has applied SciAps technology to much of his research, such as authenticating minerals in museum collections — easily more than 200 garnet analyses in one day, for example.

“Imagine these world-class institutions having a LIBS on hand to test samples and artifacts as they come in, to validate their labeled classification or discriminate between fakes and the real thing,” says Harmon.

“LIBS could also be used for museum demonstrations, as a way to engage visitors, or visitors could use a LIBS to interrogate a set of samples in a display to identify what they are.”

Open-source amplifier

Although he has written about his research and published many articles for scientific journals, Dr. Harmon is not content with LIBS researchers only publishing in spectroscopic journals. His mission is to make geologists and archaeologists aware of the benefits of LIBS analysis through publication in the journals of these disciplines.

“It’s frustrating that the scientists in the LIBS analytical community publish all kinds of interesting applications about LIBS geological and archaeological applications in their specialist community journals. Thus, information about possible applications tends not to reach the potential user community, the people who could benefit from real-time rapid analysis, either in the laboratory or field. The majority of scientists in these communities are not familiar with state-of-the-art analytical techniques, so they're generally behind the curve in this context,” says Harmon.

He believes the analytical community has the responsibility to reach out to the user community. “But it doesn't often do a very good job of that. So that’s what I want to do.” Dr. Harmon continues to write articles about handheld LIBS with that goal in mind.

Trade show guru

Harmon has been known to join SciAps at geoscience conferences and tradeshows to extol the virtues of both the SciAps handheld LIBS and XRF analyzers.

“Fieldwork with handheld analyzers will not supplant doing detailed laboratory work, but they will help us do a better job of collecting samples and understanding what we’re looking at in the field. There's no substitute for that,” says Harmon.

The four or five times he’s helped SciAps with a booth, there’s been nonstop traffic on all days of the meeting. In many cases, people were waiting or coming back later to get an up-close look at this groundbreaking technology and a user-appropriate demonstration. “It didn't surprise me because these are new tools and even people who are primarily geochemists won't necessarily know about them,” says Harmon. The more people he can reach the better, he says.

EPA, can you hear me?

Harmon is hoping to make inroads into the environmental community as well. Getting answers in the field in real time could change how contaminated soil clean-up and remediation monitoring is conducted. Harmon knows that using both LIBS and XRF (because with both analyzers, one can analyze effectively for both light and heavy elements) as tools to monitor soil could significantly lower the time and cost of contaminated soil analysis and post clean-up validation monitoring. The issue is the reluctance of the regulatory community to accept new techniques. “There's such a vested interest in not changing the standard protocols even though we now have faster, better, cheaper tools. It’s depressing sometimes to see the potential for this huge application, but we can't break into it because the EPA regulations require the use of specific sample collection approaches in the field and subsequent analytical protocols in the laboratory,” says Harmon.

“Why maintain these time-consuming and expensive protocols when we could just traverse across the area with a handheld analyzer and get the answer right away?”

With handheld LIBS, forever a kid in a candy shop

Although Harmon has worked with SciAps LIBS in labs and museums for over five years, it wasn’t until this past June that he was able to go into the field with a handheld LIBS analyzer acquired by professor Lewis Owen chairman of the Department of Marine, Earth, and Atmospheric Sciences at North Carolina State University, for analysis of rock varnish in the Mojave Desert.

“I was just like a kid in a candy shop,” says Harmon, describing the field work in California.

This fall, Harmon is hoping to travel with Owen, Richard Hark, and Michael Wise of the Smithsonian Institution National Museum of Natural History to the North Carolina mountains with LIBS in hand.

“We're hoping to do some prospecting for raw, lithium gem minerals that occur in those mountains. That'll be exciting,” says Harmon.

Harmon and Hark will also be continuing their work on California obsidian and obsidian artifacts.

“It’s a project on obsidian source discrimination and tracing artifacts to their source and thus understanding trade routes to see how indigenous people traded commodities across the western U.S.,” Harmon says.

Twenty years ago, Dr. Harmon had a vision for the future of LIBS and that future is here. “Thank you to SciAps for creating the handheld LIBS. I've been waiting a long time for it,” says Harmon. Now, he’s doing his best to bring the rest of the scientific world into the 21st century with him.

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