The 2017 Emerging Leader in Atomic Spectroscopy Award

Jan 01, 2017
Volume 32, Issue 1, pg 32–37

The winner of Spectroscopy's inaugural Emerging Leader in Atomic Spectroscopy Award is highlighted.

 


George Chan, a project scientist at Lawrence Berkeley National Laboratory (LBNL) in Berkeley, California, has won the inaugural Emerging Leader in Atomic Spectroscopy Award, which is presented by Spectroscopy magazine. This new annual award recognizes the achievements and aspirations of a talented young atomic spectroscopist, selected by an independent scientific committee. The award will be presented to Chan at the 2017 European Winter Conference on Plasma Spectrochemistry (EWCPS), where he will give a plenary lecture.

Spectroscopy created this award as a way to recognize and encourage leaders of the next generation of atomic spectroscopists. Chan’s work thus far in his early career includes shining examples of achievements in inductively coupled plasma–atomic emission spectroscopy (ICP-AES), laser-induced breakdown spectroscopy (LIBS), laser-ablation molecular isotopic spectrometry (LAMIS), and ambient ionization mass spectrometry. He is indeed a standout in the field.

An Early Focus on Science

Chan received his Bachelor of Science degree, with 1st Class Honor and a chemistry major, from the University of Hong Kong in 1997. He then worked as a teaching assistant in the Department of Chemistry at the University of Hong Kong from 1997 to 1999 with Associate Professor Wing-Tat Chan, while pursuing his master’s degree. Chan completed his master’s degree in 2000, with a thesis titled “Investigation of Matrix Effects on Excitation Conditions of Dry Inductively Coupled Plasma Using Laser Ablation.”

During those studies, Chan had two stints, in 1998 and 1999, as a visiting scientist in the Advanced Laser Technologies Group at LBNL, where his advisor had previously done postdoctoral work. At LBNL, Chan began working with Richard Russo, a senior scientist.

“Chan spent a summer at LBNL and it was immediately clear that he was a talented student,” said Russo. “He quickly learned our instrumentation and was able to perform experiments on dual laser ablation that led to several publications. He did the research and wrote the manuscripts—amazing work, and on par with the upper-level PhD students.” As a result, Russo decided to invite Chan back for a second summer in 1999 for another three months.

Chan gained a few years of professional experience before taking on his next academic challenge. From 2000 to 2001, he worked as an associate consultant in the Chemistry and Metallurgy Division at the Hong Kong Productivity Council in Hong Kong, and from 2001 to 2002, he worked as a research assistant in the Department of Chemistry at the University of Hong Kong.

Chan maintained close contact with his former advisor, Wing-Tat Chan, over the years. “From my point of view, Chan never really left. Before he went to the United States, he visited the laboratory frequently and advised students in the group on their research and careers,” said Wing-Tat Chan. “He managed to come back to Hong Kong almost every year during his PhD study and therefore still knows the group well. He is the big brother to several generations of my research students.”

In 2002, Chan went to the United States to pursue his doctorate at Indiana University, in Bloomington, Indiana, under Professor Gary M. Hieftje. Chan completed his PhD in 2007, with a thesis titled “Fundamental Mechanisms and Diagnostic Tools for Interference Effects in Inductively Coupled Plasma-Atomic Emission Spectrometry.” Chan stayed at Indiana for postdoctoral work, and in 2008, he was promoted to assistant scientist, and remained there until 2012.

Hieftje noted that Chan came to his laboratory following guidance from Russo. “Russo was previously a graduate student in my research group and I took it as the strongest sort of compliment that he would urge Dr. Chan to join us,” said Hieftje. “After performing brilliant doctoral research, Dr. Chan stayed on in my research operation, first as a postdoctoral associate and later as an assistant scientist, which is a faculty position, but oriented toward research rather than teaching.”

In 2012, Chan left Indiana University for a position as a project scientist in the energy technologies area (formerly the environmental energy technologies division) at LBNL, where he remains today. “When Chan was looking to leave Indiana University for a career position, the timing was perfect in that we had funding at LBNL for a position that would accommodate him,” said Russo, adding that Chan took a risk in accepting the role, because it was a temporary research position. “Since that time, about three years ago, we have been able to secure funding to create a more permanent position for Chan at LBNL,” Russo said.

In that role, Chan has been successful in obtaining funding from the Department of Energy (DOE) for several of his proposals. “The DOE is great for supporting next-generation scientists for National Nuclear Security Administration (NNSA) and other programs,” Russo said.

“Chan is one of the key scientists in the LBNL laser spectroscopy group,” said Russo, noting that Chan has already published several excellent manuscripts and received many invited lectures related to his research there. “I learn tremendously from him. One of the greatest parts of my job is being around, and learning from, talented young scientists like Chan.”

 

Contributions to the Field

Though young, Chan has already made significant contributions to analytical chemistry and atomic spectroscopy. One of Chan’s most significant contributions to the field of atomic spectroscopy has been his work on matrix effects and excitation processes in ICP, where he discovered several new phenomena and mechanisms. One breakthrough was his discovery that matrix elements having low second ionization potentials produce the strongest matrix effect, even though it had been widely reported in the literature that elements with low first ionization potentials produced the strongest effects. He also found that another critical parameter that governs the severity of the matrix effect is the presence or absence of low-lying energy levels in the doubly charged matrix ion; this behavior showed a very strong correlation with Penning ionization. This work cleared up some confusion in the ICP community about the importance of Penning ionization.

Chan also explained, for the first time, that charge transfer and matrix interferences in the ICP can be linked together. He then showed how to exploit plasma-related matrix effects to study charge transfer in the ICP. With his novel procedure, candidate charge transfer levels can be easily and rapidly screened and identified. Chan also provided experimental evidence that state-selective charge transfer exists even in the atmospheric-pressure ICP. These pioneering findings provide a crucial step in understanding fundamental mechanisms in the ICP.

Chan’s colleagues have taken notice of this groundbreaking research. Michael Webb, an associate professor at the University of North Carolina in Wilmington, said he was impressed by Chan’s contributions to understanding and correcting for matrix effects in ICP and other atomic spectroscopy techniques. “ICP is sometimes viewed as a solved problem because it has been so successful and because it is a relatively old technique,” said Webb. “The reality is that there is still reason to improve on even such an established technique, and Chan has shown that there is still room to do so.”

Chan’s research interests also include practical aspects of analytical atomic spectrometry. For example, Chan developed diagnostic tools to flag the presence of interferences so that immediate remedial work can be undertaken by an analyst. His developed matrix-effect indicator and method for interference compensation do not require the addition of external reagents to the sample or any prior knowledge about the content of the sample. In addition, they can be readily adopted on commercial ICP-AES spectrometers, can be easily automated, can be used during an analysis with no time penalty, and require no extra input or sample treatment by the analyst.

Steven Ray, the Winkler Assistant Professor of Chemistry at the State University of New York at Buffalo, said that Chan’s work developing this diagnostic tool is a great example of his ability to take an observation from a fundamental study and turn it into a practical purpose. “In Chan’s development of the spatially resolved emission maps as a flag for matrix effects in the ICP (and now elsewhere), he was able to use an observation from his fundamental studies of the ICP to devise a system that can immediately indicate the presence of a nonspectroscopic matrix effect in an analysis (something that still plagues ICP-AES analyses),” he said.

George Chan and a member of the Horiba French research team during the installation of the Horiba instrument in the laboratory in Bloomington, Indiana, in 2005.
Photo courtesy of Jean-Michel Mermet.

 

Hieftje considers Chan’s studies into methods for detecting the presence of matrix interferences to be his most important work so far. Many elemental determinations by ICP emission spectrometry yield erroneous results because of the unrecognized presence of matrix interferences, Hieftje explained, and that such interferences arise when other constituents in a sample affect the emission intensity of the target analyte. “To avoid such errors, most experienced analysts must resort to time-consuming and error-prone methods, such as internal standardization, matrix matching, or standard additions,” he said. “With Dr. Chan’s invention, based on the spatial behavior of analyte emission, the existence of an interference can be readily detected and, if it is present, a location in the ICP can be found where the errors are minimal or absent.”

Chan’s research interests also extend into optical isotopic analysis. Chan investigated the potential advantages of using multiple emission lines in the isotopic analysis of uranium by LIBS. His work also revealed that the primary factor dictating analytical precision is not the magnitude of an isotope shift but rather the signal-to-background ratio. Recently, he combined femtosecond-laser filamentation with LAMIS and demonstrated the first remote isotopic analysis with laser filamentation. This study combines existing knowledge about isotopic shifts in emission lines with modern-day technology (computers and a femtosecond laser) to further advance the analytical capability of optical spectrometry for isotopic analysis at potentially remote distances.

Russo thinks Chan’s work is just beginning in these optical isotopic areas, noting that Chan is quick to let people know that he is an “optical” spectroscopist, not a mass spectrometrist. “Chan understands the fundamental physics and chemistry of optical transitions in atomic and molecular spectroscopy, and the practical issues with spectroscopic measurements,” said Russo. “He has done marvelous work showing the use of optical spectra for isotopic analysis. This is a new field and one I think where Chan will continue to make significant contributions.”

Chan has also made noteworthy contributions to the characterization of fundamental mechanisms in plasma sources used in ambient ionization mass spectrometry. Although ambient ionization mass spectrometry is widely used, the processes for generating the key reagent ions in the ionization sources are not yet fully understood. Chan’s paper on this topic altered the thinking about the underlying mechanism of reagent-ion generation in plasma-based ambient ionization sources; before his work, it was thought that metastable helium atoms were the only important species in these sources. Since its publication in 2011, this work has already been cited 60 times and has the highest rate of citation of any of his published works (currently 10 citations/year).

Jacob Shelley, an assistant professor and the Alan Paul Schulz Career Development Professor of Chemistry at Rensselaer Polytechnic Institute, cited Chan’s work in ambient ionization mass spectrometry as one of his greatest contributions so far. Shelley explained that this work was done while they were both working in Professor Hieftje’s lab and in collaboration with Professor Graham Cooks’s group at Purdue University. They used a variety of optical spectroscopic approaches to better understand ionization mechanisms of a helium dielectric-barrier discharge (the so-called “low-temperature plasma probe”) for use in mass spectrometry. While examining data obtained during those collaborative visits, Chan noticed some odd trends in the Boltzmann plots for N2 emission in the plasma. Digging deeper in the plasma-physics literature and the data they had, Chan postulated a series of mechanisms that involve helium dimer ion (He2+) serving as an energy carrier from the plasma into the open atmosphere, which leads to reagent-ion formation. “To this day, it is one of the most beautifully crafted and presented studies I have seen,” said Shelley. “I am fortunate to have worked with him along the way.”

Publications, Awards, and Accolades

To date, Chan has published 51 papers and presented 55 talks at scientific conferences, including 14 invited lectures and 41 contributed oral presentations. He was also awarded a patent in 2010 with Professor Hieftje for their work with ICP–AES (1).

Ray commented that the works Chan has published in fundamental spectrochemistry in the ICP and other plasma systems have resulted in a fundamental understanding that has led to better practical utility of analytical measurement systems. “This represents a significant contribution in itself, and also one that will be long-lasting,” he said.

Professor Kay Niemax, a Wilhelm-Ostwald-Fellow at the Federal Institute for Materials Research and Testing (BAM) in Berlin, Germany, said that despite the fact that Chan is still at the beginning of his career, he is already considered one of the leading experts in plasma spectrochemistry. “In that field he has published excellent papers documenting his manifold interests and capabilities,” said Niemax. “His publications on matrix effects and their corrections in element analysis by inductively coupled plasma-optical emission spectroscopy (ICP–OES) are considered the best research papers in that particular field.”

Chan has also been the recipient of many prestigious awards, fellowships, and grants over the years. A few of those include the Spectrochimica Acta Atomic Spectroscopy Award (2013 and 2004), the Society for Applied Spectroscopy’s (SAS) Graduate Student Award (2006), the Kraft Fellowship from Indiana University (2006), and the Felix Haurowitz Award from Indiana University (2005)—just to name a few.

 

Who Is George Chan?

Chan’s friends and colleagues appreciate more than just his outstanding work, referring to him as brilliant, hard-working, creative, and enthusiastic. He was also called a modest and congenial partner who is able to work alone or in a team setting.

“He is knowledgeable, insightful, innovative, skillful, and always curious of everything related to science,” said Wing-Tat Chan. “George Chan is already recognized as one of the top scientists in analytical atomic spectroscopy.”

Ray said that Chan is famous for being a hard worker, who loves to work off-hours on many occasions because it permits him the opportunity to focus completely on his measurements. But because “nobody can work 24/7,” Ray said, Chan built a custom autosampler system by taking apart an old dilution device and hacking the computer software for a commercial ICP-AES instrument. “He even went so far as to solder wires to specific keys on his keyboard to automate his measurements,” said Ray. “He called his creation ‘virtual George.’ So, if he couldn’t be in the lab, at least ‘virtual George’ could be there!”

Gerardo Gamez, an assistant professor in the Department of Chemistry and Biochemistry at Texas Tech University, echoed Ray’s sentiments, adding that Chan does not set foot in the laboratory without a plan. Gamez also remembered “virtual George” in this context—as a tool that also allowed Chan to use his time well, by freeing him up from pushing the buttons in a long series of repetitive experiments so that he could spend more time analyzing data. “Chan does not leave any rock unturned with respect to data analysis,” said Gamez. “He is very meticulous in this sense and I think it is these characteristics, together with his determination, that have allowed him to make sense of very complex problems.”

Wing-Tat Chan had a similar story to share about Chan’s combination of a systematic approach and innovative thinking. Chan’s final year undergraduate project involved the investigation of combining a capacitively coupled plasma (CCP) with graphite furnace atomic absorption spectrometry (GFAAS), making use of the CCP to reduce the matrix effects in the AAS measurement. The instrument he was using was designed to be operated as either a conventional GFAAS or as a furnace atomic plasma excitation (emission) spectrometer (FAPES). The instrument documentation was sparse, with minimal descriptions of the hardware. Chan, a third-year undergraduate student at the time, probed the instrument using various methods to understand the implementation of background correction of the instrument and studied the plasma behavior versus furnace temperature and in the presence of water and metal ions. “He is systematic and methodological,” said Wing-Tat Chan. The project also demonstrated Chan’s ability to improvise. At the beginning of the project, the instrument was in disrepair, and a cone for the furnace interface was badly worn out. When Chan was waiting for the replacement cone to arrive (it took a few weeks for the overseas order), he came up with the idea of using a stainless steel cap for a teacup that was commonly available in local sundry markets. “The cap was eventually not needed, but his ability to improvise and innovate was abundantly demonstrated,” said Wing-Tat Chan.

Jean-Michel Mermet, a retired research director with the Centre National de la Recherche Scientifique (CNRS) at the University of Lyon, and later a scientific advisor with Horiba-Jobin-Yvon, is equally impressed by Chan’s talents. Mermet said that Chan exhibits an excellent ability to combine fundamental studies and instrumentation. “Very quickly, with his very efficient analytical mind, he can understand what is interesting in the results of an experiment and what deserves further experiments to gain a better understanding of the various mechanisms involved in ICP-AES or LIBS,” said Mermet. “He is able to develop any instrumentation he may need to facilitate his research. Not only can he produce a huge amount of work, but he can also extract the useful information from it. Moreover, he may suggest very innovative concepts, such as those related to diagnosis and compensation for matrix effects. He is certainly one of the most brilliant researchers that I ever met.”

George Chan and Steven Ray during a social event at Pittcon 2009.
Photo courtesy of Jean-Michel Mermet.

Chan also has interests and hobbies outside of the laboratory, and several people commented on his love of photography. “Chan takes beautiful photos of scenery and people that show his ‘other side’—as an artist,” said Wing-Tat Chan. Hieftje also commented on Chan’s love of spicy food, specifically hot buffalo wings that he favors whenever he is back in Indiana for a visit.

 

Future Directions

With the number of accomplishments Chan has achieved so far in his young career, the future looks very bright for him—no matter which path he chooses going forward. His friends and colleagues agree.

Webb foresees Chan starting his own research group, probably at an academic institution, soon. Niemax agreed.

“George is a brilliant scientist with the strong desire and persistence to study and understand physical and chemical processes in detail. Therefore, I see his future in academia or scientific institutions that adopt basic science on their own,” said Niemax. “I am convinced that the scientific community can expect further important contributions from him, which will advance our knowledge in science.”

Shelley had similar comments regarding Chan’s abilities, and expects that Chan’s interests and passion will soon lead to him becoming a professor at a top (“R1”) research institution, where he will mentor and teach outstanding students while exploring novel areas of optical spectroscopy and help pioneer precise isotope ratio measurements obtained with optical-spectroscopic means (the LAMIS technique described by Rick Russo and others at LBNL). “I was fortunate enough to be an indirect student of Chan’s for a few years and learned an enormous amount in that time,” he said. “Because of that, I am certain he will produce extremely intelligent, hard-working, and successful students in addition to the high caliber research he is already known for.”

Russo has similar ideas in mind for Chan, but admits that he is a little biased and would prefer that Chan continue to work with him at LBNL. “I think many universities, laboratories, and industries would find him highly valuable. My preference would be for him to stay at LBNL and become one of the recognized scientists working with the laser spectroscopy team, and the greater laboratory,” said Russo. “However, I believe that his opportunities are completely open—both in terms of what research he decides to pursue and where he decides to reside.”

Ray thinks that we are seeing Chan blossom as he expands his interests into other types of atomic spectroscopy, such as LIBS. “He can apply his deep understanding of spectrochemical phenomena to a wide range of problems in spectroscopy. Really, the sky’s the limit for Chan,” he said.

As for the Emerging Leader in Atomic Spectroscopy Award that Chan is receiving this year, his friends and colleagues could not be happier for him. Shelley and Gamez both said there is no one more deserving of this inaugural award other than Chan. “It also sets a very high bar for future winners of this prize,” concluded Shelley.

More About Chan

An in-depth interview with George Chan focused on his research, challenges, and accomplishments, will be published in the February 14, 2017, edition of our newsletter, The Wavelength. Another recent interview with Chan about his work with spatial heterogeneity can be found here: www.spectroscopyonline.com/what-icp-spatial-heterogeneity-reveals-about-interference-icp-aes-0

2018 Emerging Leader in Molecular Spectroscopy: Now Accepting Nominations

For information about how to nominate someone for the 2018 award, please see the call for nominations on our website: www.spectroscopyonline.com/emerging-leader-atomic

Reference

  1. G.C.-Y. Chan and G.M. Hieftje, U.S. Patent 7,768,639, 3 August 2010. 

 

Megan L’Heureux is the managing editor of Spectroscopy and LCGC North America magazines in Iselin, New Jersey. Direct correspondence about this article to: meg.l’[email protected]

 

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