Spectroscopy Interviews

Quantum cascade lasers have been gaining increasing attention as their capabilities are being demonstrated in a range of applications. One recent advance is the development of a miniaturized QCL, which when used as a light source, enables mid-infrared (mid-IR) scanning speeds much faster than those of conventional Fourier-transform IR (FT-IR). Ralf Ostendorf of the Fraunhofer Institute for Applied Solid State Physics (IAF) in Freiburg, Germany, recently spoke to Spectroscopy about this work.

Matthew Baker of the University of Strathclyde in Glasgow, Scotland, has been using infrared spectroscopy for the analysis of biological samples. The noninvasive procedure allows for the rapid detection of diseases and provides an opportunity for early administration of a therapeutic strategy, when the treatment is most effective. Spectroscopy spoke with him about his work in this area using attenuated total reflection (ATR) and ATR combined with Fourier transform infrared (FT-IR) spectroscopy.

Air quality is a global concern, but even more so for urban areas and poor countries. The pollution in the air goes directly into our lungs, which makes monitoring the particulates and various levels of pollution a major concern. Johan Boman of the Department of Chemistry & Molecular Biology at University of Gothenburg has been studying the air quality in several different regions using energy dispersive X-ray fluorescence (EDXRF) and total reflection X-ray fluorescence (TXRF). Here, he discusses the challenges faced in this research and plans for future studies.

Inductively coupled plasma–mass spectrometry (ICP-MS) has become a successful approach for fast, multielemental analysis, and analysts are applying it to a wide range of analyses, including geochemical, environmental, forensic, and medical studies. Uwe Karst is a Professor and Chair of the Analytical Chemistry Department at the University of Münster in Germany, and he and his group use ICP-MS for applications such as analyzing magnetic resonance imaging (MRI) contrast agents in river water, speciation analysis in a study of a disease related to renal failure, and examining the distribution of a labeling compound in mouse tumor cells and macrophages. He recently spoke to us about this work.

Inductively coupled plasma (ICP) sources have been around for so long that most scientists don’t even question their capability to get the job done. However, an ion source for elemental mass spectrometry (MS) has been developed that offers different benefits compared to ICP sources: the liquid sampling-atmospheric pressure glow discharge (LS-APGD) ionization source, which features small sample volumes, low uptake rates and waste, and low operating power.

Imaging techniques using vibrational spectroscopy, mass spectrometry (MS), and atomic force microscopy have all been advancing and gaining momentum in recent years. There is great potential power in these imaging techniques, particularly in the biomedical field. Thomas Bocklitz of at the Friedrich-Schiller-University Jena is working to better harness the power of these techniques by combining them.

Laser-induced breakdown spectroscopy (LIBS) is an ideal technique for elemental analysis in industrial applications because of its fast response and high sensitivity, and its ability to be used for real-time, noncontact analysis.

Diffuse reflectance is a well-known sampling technique in mid-infrared (mid-IR) and near-IR spectroscopy. Despite its significance, however, the underlying mechanism of the technique is not well understood-particularly in mid-IR diffuse reflectance. Eric B. Brauns, an Associate Professor at the University of Idaho, has developed an instrument capable of studying the mechanism, using time-resolved measurements. Brauns won the 2015 Applied Spectroscopy William F. Meggers Award for this work (1). He recently spoke with Spectroscopy about his award-winning paper and what it means for the field.

Selenoproteins play an important role in human physiology and health, and as a result, sensitive methods are needed for their analysis. Joanna Szpunar of the National Research Council of France has been working with bioinorganic speciation analysis and hyphenated techniques for metallomics studies for some time. She recently spoke to Spectroscopy about using laser-ablation inductively coupled plasma–mass spectrometry (LA-ICP-MS) to detect trace levels of human selenoproteins in cell extracts and about her work with ICP-MS-assisted electrospray tandem MS for the identification of selenium-containing proteins in rice grown on seleniferous soils.

UV resonance Raman spectroscopy examines how UV light interacts with the electrons of samples and provides information about their molecular structure and dynamics. Sanford A. Asher, Distinguished Professor of Chemistry at the University of Pittsburgh, is using the technique to study peptide excited states and conformations and protein folding, with the ultimate goal of helping to advance research into the mechanisms of disease. He recently spoke to us about this work.

Roughly half of all promising new drug candidates are abandoned because of poor aqueous solubility. As a result, many pharmaceutical researchers are pursuing amorphous formulations, which can show improved solubility. Those researchers need powerful analytical tools to study the trace crystalline structures in those drugs, however. To address this problem, Garth Simpson of Purdue University has developed a powder X-ray diffraction (XRD) method with 100 ppm detection limits. He recently spoke to us about this work, for which he won the 2014 FACSS Innovation Award.

Inductively coupled plasma (ICP) systems have an optimal observation height, but measurements made at other observation heights in the ICP should also yield the same accurate analytical results - if there are no interferences.  This means that a spatial-varying determined concentration of the analyte can reveal that something - such as matrix interference - is wrong with the measurement. George Chan of the Laser Technologies Group at Lawrence Berkeley National Laboratory recently spoke to us about his work exploiting the spatial heterogeneity of the ICP.

Classic proteomic workflows analyze tryptic peptides, which generally weigh less than 3000 Da, using a “bottom up” approach. The importance of multiple and coordinated post-translational modifications compels the analysis of longer peptides (using “middle out” analysis) and intact proteins (using “top down” analysis). Prof. Catherine Fenselau of the Department of Chemistry and Biochemistry at the University of Maryland is a leading researcher in this field, and has won numerous awards for her work, the most recent of which is the 2014 Eastern Analytical Symposium Award for Outstanding Achievements in Mass Spectrometry. She recently spoke to us about her research with mass spectrometry–based analyses of proteins associated with cells known to be an obstacle to anti-cancer immunotherapies.

Infrared spectroscopic imaging has been advancing significantly in recent years. Key to that advance is improving the understanding of the underlying mechanisms that influence the ability to achieve greater resolution and speed. Rohit Bhargava, a professor in the Department of Bioengeering and at the Beckman Institute at the University of Illinois, Urbana-Champaign, has been elucidating those mechanisms, and won the 2014 Applied Spectroscopy William F. Meggers Award for his paper on this topic. He recently spoke to Spectroscopy about this work.

Lasers have many different scientific uses. Some analytical scientists are advancing the use of laser-based techniques to analyze works of art and other ancient artifacts. Laser-ablation surface-enhanced Raman microspectroscopy (LA-SERS) can analyze art and artifacts to accurately identify the various components inside them. Spectroscopy recently spoke with Pablo Londero, an Associate Conservation Scientist at the Institute for the Preservation of Cultural Heritage (IPCH) at Yale University, and Marco Leona, the head of scientific research at the Metropolitan Museum of Art, about their work in this area.

Christian Pellerin, a professor in the Department of Chemistry at the University of Montreal in Canada, is using Raman spectroscopy and the most probable distribution method to quantify the orientation of polymers and electrospun fibers. Spectroscopy recently spoke with him about this work.

An interview with Allison Stelling, a recent PhD from Prof. Peter Tonge's group at Stony Brook University in New York, exploring the use of IR spectroscopy for use in intraoperative diagnostics during brain surgery.

Fourier transform infrared (FT-IR) spectroscopy has been used to identify unknown materials, determine the quality or consistency of a sample, and determine the amount of components in a mixture. Gary Small, of the Department of Chemistry and Optical Science and Technology Center at the University of Iowa, spoke to Spectroscopy about his work using passive FT-IR remote sensing measurements.