A Look at the Sensitive Fluorescence Detection of Nitrite Ion Under Mild Conditions

A Facile Synthesis of Tannic Acid–Protected Copper Nanoclusters 

2021 Review of New Spectroscopic Instrumentation

Raman Spectroscopy in the Detection of Breast Cancer

Analyzing Water Samples Using EPA Method 200.8 to Support the Lead and Copper Rule Revisions

Jerome Workman Jr. serves on the Editorial Advisory Board of Spectroscopy and is currently with Unity Scientific LLC. He is also an adjunct professor at Liberty University and U.S. National University. He can be reached at jworkman04@gsb.columbia.edu.

Inductively-coupled plasma-optical emission spectroscopy (ICP–OES) and ICP–mass spectrometry (ICP–MS) are often considered mature techniques, but researchers know that some aspects of the techniques are still not fully understood. Probing the mechanisms involved can lead to more accurate results, and in some cases may cast doubt on accepted explanations. John W. Olesik, who directs the Trace Element Research Laboratory (TERL) in the School of Earth Sciences at The Ohio State University, has spent many years studying the processes that control signals in ICP techniques, and yet he is still encountering surprises. He is also in a unique position to get involved in exciting, applied research collaborations, because the TERL also provides elemental analysis and access to ICP–OES and ICP–MS instruments to groups throughout (as well as to clients and collaborators outside) the university, leading to all sorts of collaborations. This interview is the second part of a two-part series. In this part, Olesik discusses environmental research, data analysis techniques, and his collaborative research philosophy.

You are currently involved in a research study to analyze the effects of environmental exposures of metals on newborns and child health (1). What can you share with us about the challenges in analyzing human placenta samples for a variety of metals?

There have been two main challenges. First, some of the elements of interest (including Pb, Pt and Gd) are normally present at extremely low concentrations (low parts per trillion) in many of the digested sample solutions. We also need to measure the pattern of naturally occurring rare earth elements, all present at extremely low concentration, to identify anthropogenic Gd (Dramatically elevated anthropogenic Gd concentrations in placentas come from retention of a small fraction of the approximately 1 g of Gd injected for a Gd chelate contrast enhanced MRI, even if the MRI was done years earlier. In some cases we are detecting much lower, but elevated anthropogenic Gd in the placentas from mothers who never had a Gd-contrast enhanced MRI. We are trying to identify the source of anthrogenic Gd in those cases.). This requires careful control of potential sources of contamination, and a means to avoid potential spectral overlaps. Second, the samples are not all in the same form as we receive them, because they are coming from a variety of sources that use different sample preservation processes. As a result, we have had to develop different sample preparation procedures for the different sample forms, and in many cases for a very limited amount of sample.

You are working on a project to identify and geochemically characterize atmospheric mineral nanoparticles in pre-industrial Antarctic ice during the last climatic cycle (2). How did this project come about? What is your role in analyzing these nanoparticles? What would you expect to find? 

Many of our collaborations have begun after another research group designed experiments and came to us about the trace element measurements, either before or after submitting a proposal, or even after they had funding. This project is one where we were involved from the conception of the idea. Lonnie Thompson and Ellen Mosley-Thompson lead a group in the Byrd Polar and Climate Research Center (BPCRC) at Ohio State that has built one of the largest collections of ice cores in the world through many incredible expeditions, not only to the polar regions but to locations far from the poles at high elevations. They are incredible explorers and scientists. Ice core drilling equipment has to be brought to the site (up mountains at high elevations in non-polar regions). After the ice cores are drilled, the cores need to be brought back down the mountain, and then transported, without melting, back to Ohio State laboratories.

The ice cores, the gases trapped in them, pollen and other biological materials, and particles (deposited from the atmosphere and entrapped in the ice) provide a historical record of climate through time. The depth within the ice core can be related to the date it formed, providing a time scale.

Paolo Gabrielli is a research scientist who has worked at Ohio State with the Thompsons since 2007. Paolo is a glaciologist who also has extensive experience using ICP–MS to measure trace elements in the ice or entrapped as particles. Using the “elemental fingerprints,” sources of particles (“dust”) may be identified. However, the vast majority of elemental chemical measurements to date have been done using acid to digest and dissolve the “dust” (consisting of many particles with a range of sizes) and then measure the bulk (average) elemental composition. Both BPCRC and TERL have the same model ICP-sector-field–MS instrument, so we have sometimes borrowed components from each other’s instrument to troubleshoot instrument problems. Paolo was also very interested in the studies of the fundamental processes that occur in the plasma being done in my laboratory, as well as new applications, including single particle ICP–MS.

Following our discussions, Paolo pointed out: there were very little data on the elemental chemical composition of individual particles entrapped in ice cores, and what data there were had been based on small numbers of particles measured using electron microscopy with energy dispersive detection. Furthermore, there was little information on the number concentration of particles less than about 0.5 μm even though the number of particles smaller than 0.5 μm is expected to be orders of magnitude more the than the number of particles larger than 0.5 μm.

Upon further discussion, we also realized that if we could measure the composition of many individual particles that had been trapped in ice cores, we could potentially much more effectively determine the types of particles (for example, particular minerals or anthropogenic materials) present, and therefore their sources, compared to bulk measurements that provided an average composition. Furthermore, small percentages of unusual particles were likely lost in the “noise” of bulk measurements.

We then worked together on a proposal to the National Science Foundation (NSF), not having a feel for the chances of getting funding and expecting it would require more than one iteration and submission before it might be successful. Our plan was based on a combination of complementary measurement techniques, including two that were typically used in previous studies of trace elements in ice cores—Coulter counter based particle size distributions and ICP-sector field–MS measurements of bulk measurements of particles following acid digestion—along with techniques to measure individual particles (single particle ICP–quadrupole MS, single particle-ICP–TOF–MS, and transmission electron microscopy with energy dispersive X-ray spectroscopy). We added two world-class collaborators to support the proposal and to fill in capabilities that were needed but not available in our labs: James Rainville of the Colorado School of Mines, to measure nanoparticles sizes with field flow fractionation-ICP–MS, and Frank von der Kammer, who had an ICP–TOF–MS in his laboratory at the University of Vienna. Both also are among the world’s experts in studying the fate of nanoparticles in the environment. Paolo and I are both involved in nearly aspect of the project other than acquiring and cutting the ice (Paolo is also involved in that, but I am not).

Four of the five reviews we got back on the first submission of the proposal were among the most glowing I have ever seen regarding the importance and novelty of our goals, and the quality, logic, and completeness of our plans to try to accomplish those goals. Occasionally, when I’m having a “difficult” day, I go back and re-read them with a big smile. The fifth reviewer submitted a very short review that was not positive and commented: “The proposal reads more like ‘We want to use every analytical tool we have’ than ‘Here are the questions we are trying to answer and here is how we will attempt to answer those questions.’” Despite that comment, the project was funded.

The pre-industrial Antarctic ice will provide insight into natural nanoparticles and microparticles, transported to Antarctica from the rest of the world, and how the number and elemental composition of those particles have changed over the last 40,000 years. In addition, we want to determine how much the nanoparticles (<200 nm) contribute to the total trace element concentrations, and how the microparticles (0.2 to 5 μm) contribute. Currently, this is a total unknown. Particles in the atmosphere can affect climate because they reflect, scatter or absorb sunlight and act as nucleation sites for formation of clouds. In addition, Fe-containing nanoparticles, transported through the atmosphere, may be an important source of Fe in the oceans. We also plan to measure particles entrapped in ice cores from other locations, such as Mt. Ortles in the Alps, over the last 7000 years to assess how nearby human activity, including the production of anthropogenic particles from industrial processes, has affected the number and composition of particles deposited from the atmosphere over time.

Have you had to develop any specialized chemometric techniques for your various applications of ICP–MS methods? What has been your greatest data analysis challenge in performing your research? In a more general sense, what were some of the major challenges you have encountered during your career of laboratory research? How important is sound experimental design in your work?

A number of chemometric techniques, including discriminant analysis and principal component analysis, are used to determine the best elemental “fingerprints” for comparing water composition to fish ear bone composition. Our collaborators relate trace element fingerprints in the bone samples to the trace element patterns in water in order to compare the element patterns in fish ear bones. We are also developing approaches using MATLAB programs, Excel filtering, and potentially machine learning approaches, to identify different mineral types in large numbers of nanoparticles and microparticles.

However, we also always look manually at raw data, and are constantly asking what factors other than the ones we are trying to assess could affect the data. For many samples, this includes potential sample matrix-induced changes in sensitivity and potential spectral overlaps in optical emission or mass spectra. We have spent a lot of time studying both matrix effects and spectral overlaps in both ICP–OES and ICP–MS, so we apply what we have learned to samples we analyze. For samples we measure for clients, we are constantly looking for multiple ways to measure the same element. This can include three or four different lines for optical emission, or sets of isotopes where possible for ICP–MS. We look for diagnostic signals that tell us about the plasma temperature, such as Ar emission or mass spectrometry intensities, concentrations based on both ion and atom emission intensities, ion-to-atom emission intensity ratios for the same element, or ratios of ion signals for elements with high ionization energy to elements with low ionization energies. These provide hints to when matrix effects or spectral overlaps are occurring for particular samples. The ultimate goal is to develop “intelligent instruments” that can diagnose analysis problems and take the appropriate steps automatically to overcome or avoid the potential sources of error. At a minimum, the intelligent instrument would warn the operator when the results for a particular sample might not be accurate.

Experimental design in terms of appropriate sample preparation, and careful measurement of process blanks to assess and avoid contamination (especially when measuring part per trillion concentrations) is critical. Statistically appropriate design of experiments prior to sample analyses is also essential for questions some of our clients and collaborators are trying to answer.

Occasionally, we are frustrated with clients who just want numbers now, or who are not willing to do the painstaking, time-consuming work to ensure contamination is not a problem, or who have not thought ahead about how they will interpret the analytical results. In one case, the client expected to see increasing concentrations by about a factor of 10 across a set of 10 samples. After refusing to measure blanks first because they needed results now, they measured their samples; all had the same concentration (most likely because their reagents were contaminated so the measurement was of the contamination in the reagents rather than the results of their experiment). My PhD research advisor used to ask us, “If you don’t have time to do it right, how are you going to have time to do it over?” Occasionally, clients also tell us we must have made an error in our measurements because the results are not what they expected. We treat these situations as a challenge for us to teach them.

Too often when we ask what accuracy and precision is needed to address the research question of interest, the answer we get is either “I don’t know” or “The best you can do.” Neither is a good answer. If you don’t know what accuracy and precision you need, how will you know if your results are statistically significant? “The best we can do” could mean using techniques developed by a group at NIST (National Institute of Standards and Technology), and extended by our group that is limited by the precision and accuracy of weighing out standards, not the precision of the measurement instrument. We have shown we could obtain 0.1% relative uncertainty in element concentration measurements rather than the more typical 10% uncertainly. The down side: time and cost of “perfectly” matrix matching standards to the samples and using “perfectly” matched internal standards with sample-standard-bracketing so it might take 20 hours to make the standards and measure 10 samples instead of one hour to make standards that are not perfectly matrix matched and 5 minutes per sample measurement. Another teaching opportunity!

I often remind my students that “weird results are good,” as long as you can prove the weird results are not due to a measurement error or a factor that was not considered. “Weird” results are an opportunity to learn something new from unexpected results. The lack of dependence of analyte mass on ICP–MS matrix effects is one of those “weird” results.

What would you consider to be the most meaningful contributions of your research work? What is most exciting to you about your work?

My first reaction is that is something that is probably best answered by others. I think the biggest impact in general has been to make the processes that control ICP–OES and ICP–MS signals, potential sources of error, and potential means to overcome those errors more clearly understood by others. Others may include researchers, ICP–OES users, ICP–MS users, and students both in our laboratory and in the laboratories we have had close collaborations with who have had an impact in their positions after finishing at Ohio State.

Certainly, there are several investigations done in our laboratory that I am particularly fond of. Our laboratory, and Paul Farnsworth’s group at Brigham Young University, independently, but almost simultaneously, unexpectedly discovered that some sample aerosol droplets and desolvated particles survive in the >6000 K ICP and can cool a surprisingly large volume (about 2 mm wide) of the plasma surrounding each. Several students in our laboratory did a superb job using those effects to gain a better understanding of fundamental processes in the plasma.

Later, a series of experiments injecting monodisperse droplets into an ICP to separately investigate droplet desolvation, particle vaporization, atomization, ionization, diffusion, and ion transport from the atmospheric plasma through the mass spectrometer was challenging, exciting, and provided clarity that was previously unattainable. Those experiments led us, about 10 years later, to join other groups developing and using single particle ICP–MS to measure large numbers of engineered nanoparticles and most recently mineral and other nanoparticles and microparticles entrapped in ice cores.

Some of the students in my laboratory also made great efforts to investigate ion-molecule reactions to overcome spectral overlaps in ICP–MS, and others study the fundamental basis, requirements, capabilities, and limitations of single particle ICP–MS for micro- and nanoparticle analysis.

A small fraction of the work we have done on the fundamental processes involved in ICP–OES and ICP–MS was funded by NSF. NSF then decided that all the related questions had been solved. Certainly, our recent work on matrix effects in ICP–MS showed that was not correct. Fortunately, we have had an almost 30-year long collaboration with PerkinElmer, who have supported our continuing research in that area.

While I’ve been criticized for not publishing more, and we certainly have made mistakes in some of our publications, I have been demanding that only data that are proven to be reproducible, that we are convinced are not biased by processes other than those we used in explaining the results, and that have something new and potentially important to say, are published. We have learned lots from experiments that “failed” or were not complete enough for us to decide to publish them in scientific journals; many of those were important to our learning process, and were included in theses and openly discussed at conferences.

What words of wisdom do you have for any young people interested in a scientific research career?

Find something you enjoy doing and are passionate about, and do it the best you can. It will not be easy (most easy things have already been done), but with determination, the opportunities are incredible. Before joining a research group, find out how the group is operated (there are many successful ways to run a group; you need to find a style that fits with yours). That may be as important or more important than the research topic. It is more important to learn how to do research in graduate school than what specific research you work on. That is much easier to do in the right environment for you.

Don’t limit yourself. Grades are not necessarily an indicator of future success. Learning and being able to use what you learn is more important. In my view, just “learning” to get an A and then forgetting the information so you are not able to use it in the future is a waste of time and someone’s tuition money, and does not lead to future success. The most successful graduate student I have ever had in my research group ended up in my group because no faculty in the Chemistry Department would take him; his grades and test scores weren’t great. It turned out he could learn independently and from others, he could apply what he knew to entirely different problems, he had great determination even after “failed” experiments, and he openly shared what he knew and learned.

1. Ohio State subaward: T.H. Darrah (PI), J.W. Olesik (coPI), “Human Placental Morphology, Function, and Pathology: Relationship to environmental Exposures and Newborn and Child Health” (National Institutes of Health Study, Bethesda, Maryland), NIH R011ES029281-01.

2. P. Gabrielli and J.W. Olesik, “Atmospheric Mineral Nanoparticles in Antarctic Ice during the last Climatic Cycle” (National Science Foundation Study, Alexandria, Virginia), NSF #1744961.

 is a Research Scientist and Adjunct Associate Professor in the School of Earth Sciences at The Ohio State University. John and his group, the Trace Element Research Laboratory (TERL), are focused on: 1) investigating the fundamental chemistry and physics to convert samples to atoms, ions, and signals, 2) enhancing capabilities provided by plasma-based instruments for elemental analysis, and 3) applying plasma spectrometry for analysis of biogeochemical, geological, biological, medical, pharmaceutical, and environmental samples including micro- and nano-particles. John serves on the Editorial Advisory Boards of 

Journal of Analytical Atomic Spectrometry

. He received the Society of Applied Spectroscopy Lester Strock Award in 2001 and the Spectrochemical Analysis Award from the American Chemical Society in 2009.

 is the Senior Technical Editor for Spectroscopy. Direct correspondence to: 

Articles

John W. Olesik of The Ohio State University discusses his collaborative ICP–OES and ICP–MS research and shares insights gleaned over a career of teaching and research.

Fundamental Research Collaboration and Applications of ICP-OES and ICP-MS Toward Improved Understanding of Elemental Chemical Analysis

annual product review has become a go-to source for keeping up with the latest spectroscopy instruments, components, accessories, and software. In it, you can find everything that has been launched over the past 12 months, including at the most recent Pittcon event. Here, we offer highlights of the 2021 review, which appeared in our May issue, featuring new products in the atomic, Raman, and infrared (IR) categories of spectroscopy.

Agilent Technologies featured a helium mode collision cell and half mass correction to control polyatomic and doubly charged ion interferences.

Exum Instruments, Inc. introduced Massbox, the first commercial instrument combining laser ablation and laser ionization under vacuum.

Lightigo exhibited FireFly, an instrument specializing on chemical imaging of solid samples and featuring a motorized objective turret, laser microfocus, and long depth of field. Lightigo’s FireFly could have also been placed in the “Imaging” category.

PerkinElmer, Inc. presented two instruments. The first is the Avio 560, an inductively coupled plasma–optical emission spectrometer (ICP-OES) instrument. The second is the NexION 5000 Multi-Quadrupole ICP-MS, the first ICP-MS instrument in its category to boast four quadrupoles, and engineered to meet and exceed the demanding requirements of ultratrace elemental analysis.

Thermo Fisher Scientific launched the Neoma Multicollector ICP-MS, featuring a new detector array that covers the broadest range of isotopic applications with Qtegra Intelligent Scientific Data Solution (ISDS) software.

See the details of all atomic spectroscopy products 

B&W Tek LLC, a Metrohm Group Company, showcased three Raman spectrometers. The PTRam is a self-monitoring, self-calibrating high-performance 785-nm Raman spectrometer designed for 24/7 operation. The TacticID Mobile Handheld Raman spectrometer is a handheld 1064-nm Raman spectrometer, featuring a 5-in touch screen. The TacticID-1064 ST is a handheld spectrometer that can safely analyze samples through transparent, semitransparent, and opaque packaging to reduce response time (its 1064 nm excitation produces a fluorescence-free spectrum) and can be integrated with the MisaCal mobile app.

Metrohm USA presented two Raman spectrometers. The Mira P Raman spectrometer makes it possible to build custom analytical methods that capture variations of complex natural product starting materials for biopharmaceutical production. The Misa Raman spectrometer is a portable analyzer system used for rapid, trace-level detection and identification of food additives and contaminants, and features a small footprint and long battery life.

Nanobase, Inc. showed its XperRF hybrid Raman spectrometer, which is a Raman microscope with fluorescence lifetime imaging and TCSPC features. It has a transmission spectrometer for over 90% spectrum peak efficiency. This product could also fall in the “UV-vis” and “Imaging” categories.

Ocean Insight presented the QE Pro-Raman+, which is a modular spectrometer for 785 nm Raman excitation applications. The QE Pro-Raman+ is a high-sensitivity instrument with a spectral range from 150 to 3000 cm

, plus low noise electronics and a TEC-cooled optical bench.

The Renishaw Virsa Raman Analyzer features fiber optic probes equipped with LiveTrack focus-tracking technology, enabling the analysis of microscopic areas of large objects with irregular surfaces, and enabling the measurement of large samples that will not fit under a conventional microscope.

Wasatch Photonics showed the WP 532 EXR, an extended-range Raman spectrometer that offers high signal, fast measurements, and low limits of detection. The design uses the company’s VPH transmission gratings and an f/1.3 input for maximum signal collection. The WP 532 EXR could also apply to the “UV-vis” category.”

See the details of all Raman spectroscopy instruments 

Ocean Insight’s NanoQuest spectral sensor Fourier-transform IR (FT-IR) spectrometer features a micro electro mechanical system (MEMS)–based FT-IR spectrometer that is smaller and more accessible than traditional laboratory-based instrumentation. The MEMS technology allows for a continuous-wave Michaelson interferometer to be created monolithically on a MEMS chip, which enables detection of all wavelengths simultaneously across the 1350–2500 nm range, using a single-photodetector design. This product could fit into the “NIR” category.

PerkinElmer, Inc. presents three FT-IR instruments. The Spectrum Two+ is a compact, powerful, and portable FT-IR spectrometer for routine compositional and quality analyses, providing fast and accurate results. The Spectrum 3 FT-IR Spectrometer, is a tri-range instrument with full integration. The EGA 4000 is the world’s first fully integrated thermogravimetric analysis-infrared spectrometry (TG-IR) system for evolved gas analysis (EGA). The Spectrum 3 could also apply to the “NIR” category.

See the details of all IR spectroscopy instruments 

Avantes B.V. introduced the AvaSpec-Mini-NIR Compact NIR spectrometer, which is the size of a deck of cards and is USB-powered, making it easy to integrate into other devices and handheld applications.

Galaxy Scientific Inc. introduced the QuasIR 2000 with a large area diffuse reflectance probe fiber optic FT-NIR spectrometer; this probe is designed to enable more accurate and repeatable NIR measurements of inhomogeneous samples.

Metrohm USA’s DS2500 Liquid Analyzer features smart accessory technology, integrated temperature control to 80 °C, and automatic background correction.

Sensors Unlimited has a high-speed, extended InGaAs photodiode linear array that offers extended wavelength range of 1.1–2.6 μm. This product could also apply to the “Components” category.

Surface Optics Corporation’s 410-Solar-i Portable Vis-NIR Reflectometer features a battery-operated handheld reflectometer for portable solar reflectance and absorbance measurements. This product could also apply to the “UV-vis” category.

Viavi Solutions Inc. presented three NIR instruments. The MicroNIR PAT-L is specifically designed for liquid applications as an immersion NIR spectrometer that features multiple configurations and various mounting options for diverse applications. The MicroNIR PAT-Ux features good manufacturing practice (GMP)–compliant software with an optional open platform communications (OPC) add-in and a rapid acquisition time. The MicroNIR PAT-Wx is rated for hazardous locations and certified as being compliant with ATmospheres EXplosible (ATEX), International Electrotechnical Commission System (IECEx), and National Electrical Code (NEC) requirements.

See the details of all NIR spectroscopy instruments 

To read the complete article, which includes an overview of trends, and products in additional categories such as imaging, mass spectrometry, software, UV-vis, X-ray, accessories, and more, please see the May issue of Spectroscopy in print or online at 

https://www.spectroscopyonline.com/view/2021-review-of-new-spectroscopic-instrumentation

Spectroscopy’s annual product review has become a go-to source for keeping up with the latest spectroscopy instruments, components, accessories, and software. In it, you can find everything that has been launched over the past 12 months, including at the most recent Pittcon event. Here, we offer highlights of the 2021 review, which appeared in our May issue, featuring new products in the atomic, Raman, and infrared (IR) categories of spectroscopy.

Highlights of Spectroscopy’s 2021 Review of New Spectroscopic Instrumentation

In recent years, concerns have arisen about the potential accumulation of lanthanides, like lanthanum and gadolinium, in the human body as a result of their use in clinical treatments or imaging contrast agents, or from exposure through drinking water contaminated with contrast agents. Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) imaging, which can provide spatially resolved quantification of trace elements in biological samples, is a powerful tool to investigate these questions. Uwe Karst, of the University of Münster in Germany, has been conducting research in this area, and he recently spoke to us about this work. Karst is the 2021 recipient of the Lester W. Strock Award from the New England Chapter of the Society for Applied Spectroscopy (SAS). This interview is part of an ongoing series of interviews with the winners of awards that are presented at the annual SciX conference, which will be held this year from September 26 through October 1, in Providence, Rhode Island.

In a recent study (1), you investigated the deposition of lanthanum in two patients who received lanthanum carbonate as a phosphate binder due to chronic kidney injury and compared it to additionally found gadolinium deposition resulting from its use as an MRI contrast agent. What are the benefits and risks associated with using these chemicals on human subjects?

This complete research area is based on findings that gadolinium from magnetic resonance imaging (MRI) contrast agents may be deposited in different parts of the human body. This was first found around 2006, when a nephrogenic systemic fibrosis was discovered, caused by deposition of gadolinium in the lower parts of the skin, the dermis. This disease was found to occur only for terminally kidney insufficient patients who received gadolinium-based contrast agents (GBCAs) with linear ligands, while it was not observed for patients who were treated with GBCAs with macrocyclic ligands. In 2015, depositions in the dentate nucleus and other areas of the human brain were found, and, again, they were mainly observed for patients given GBCAs with linear ligands, thus causing significant concern among radiologists. However, despite these discussions, GBCAs remain essential tools for the diagnosis of several diseases, including brain tumors and many others.

Lanthanum carbonate is administered to dialysis patients orally in quantities of up to three grams of lanthanum daily. In the stomach, it is dissolved in the acidic environment, and “free” lanthanum(III) ions are released that may subsequently precipitate and be excreted with phosphate from the patient's blood as lanthanum phosphate. Studies on the total concentration of lanthanum in the human body after significant use of lanthanum carbonate by patients showed only a limited deposition of this element in different organs. For this reason, lanthanum carbonate is considered to be relatively safe for patients compared with other phosphate binders. However, a major reason for its limited use is its comparably high price..

Was the correlation between deposition sites of lanthanum and gadolinium expected or surprising?

At the first sight, the co-deposition of both lanthanides is not surprising, considering the chemical similarities of all lanthanides. On the other hand, the chemical binding forms, or species, of both elements, as they enter the human body, differ strongly. For gadolinium, the respective stable complexes are injected intravenously; for lanthanum, a limited quantity of "free" La3+, likely complexed with small endogenous ligands, is taken up, while the majority is excreted as lanthanum phosphate or lanthanum hydroxide.

Lanthanum can therefore be considered as proxy for "free" gadolinium, which might enter the body after oral uptake of contrast agents, such as from contaminated drinking water. It should be considered that the stability of the GBCAs under acidic conditions, including those in our stomach, is limited, giving rise to the expectation that oral uptake of GBCAs would lead to exposure towards “free” lanthanum(III) ions rather than the intact GBCAs. For this reason, our results clearly show that the exposure of humans to the lanthanides strongly depends on the respective binding forms, but that released Gd(III) and La(III) are found in the same areas of the body, as could be expected.

Spatial distribution of gadolinium and lanthanum was determined by quantitative LA

MS imaging of tissue sections. How many tissue types were sampled, and what are the benefits to using LA

MS imaging for this analysis over other analytical techniques?

Although we tried to obtain a much larger number of patient samples, one of the challenges of this work was to draw conclusions from the limited number of only two patients. From only one of these patients, we received and investigated several tissues, including cerebellum, thyroid gland, muscle, and liver. LA-ICP-MS imaging was crucial in this work to quantify the concentration of gadolinium and lanthanum in a spatially resolved manner in all of these tissues, thus allowing us to obtain data on the distribution of these and other elements. The paper shows, for example, that the distribution of Gd and La in the vessel walls of the dentate nucleus within the cerebellum is literally identical, but with much larger concentration ratios between Gd and La in this sample than in other organs, thus providing the information that intact GBCAs will have easier access to the brain than “free” lanthanide ions, as in the case of lanthanum carbonate.

LA-ICP-MS is the only easily accessible technique that is able to provide information concerning spatial resolution in the low- to mid-micrometer range and with ppm- to ppb-concentration sensitivity rapidly, and only synchrotron X-ray fluorescence (SXRF) could provide similar information at all, although with strongly limited access to the required large-scale facilities.

What conclusions have you come to so far in your research, both analytically and clinically?

The research of several groups worldwide, including ours, confirms that LA-ICP-MS indeed is a very powerful method for spatially resolved quantification of trace elements in biological samples. The conclusion of this particular work is that oral administration of GBCAs as contamination in drinking water or other sources may result in completely different pathways than intravenous application during medical diagnostics. This is important as people start speculating about human exposure from environmental contamination of GBCAs that may increase in the future, due to increasing medical use of GBCAs.

What special sample preparation techniques are used for this method?

LA-ICP-MS in general only needs limited sample preparation, as samples can be analyzed as thin tissue slices with approximately 3-10 µm thickness, prepared in the same way as pathologists do. Traditionally, pathologists first rinse their samples with increasing amounts of ethanol, followed by increasing amounts of xylene, and finally paraffin embedding. This way, samples can be stored as paraffin blocks at room temperature literally for decades, and the quality of tissue slices for histology even after a long time remains excellent. For LA-ICP-MS, it has to be considered that not only physical sample integrity has to be preserved, as it does for pathology, but that the chemical integrity of the sample has to be preserved as well. Therefore, we always have to consider that no sample constituents should be washed out or carried into the sample to avoid artifacts. Therefore, cryosamples, obtained by rapid freezing of the samples down to -78 °C, often are the method of choice, although cryoartifacts may alter the quality of the tissue slices. In real life, the vast majority of samples will be based on paraffin embedding, and their usefulness depends on the chemical species to be analyzed.

What are the biggest challenges or limitations that you have encountered in developing this method?

In most cases, major challenges are associated with sample preparation in these highly interdisciplinary projects. Earlier work by our group, for example, has shown that intact GBCAs are rapidly washed out from tissues by paraffination and deparaffination procedures, while Gd, which was deposited by dechelation in tissues, may remain there during these processes. Therefore, sample preparation has to be discussed with our cooperation partners from medicine and biology prior to starting any major projects. In this particular case, we were interested in deposited Gd and La, so paraffinated samples were suitable.

What options or alternatives are available to overcome these challenges?

Actually, only a limited number of other options remains. Even if SXRF were available to the required extent, the same challenges would apply, as they are more linked with sample preparation than with the elemental imaging method itself. Over the years, we have learned that it is essential to begin any cooperation with a very clear discussion about what our cooperation partners from medicine and biology can expect with respect to limits of detection, spatial resolution, and information about the analyte. On the other hand, we have to clearly state our requirements regarding sample preparation (paraffin vs. cryosamples) and the consequences that arise, in terms of what analytical information can be obtained, depending on the sample type. As a chemist, I am always excited to see how much more we can achieve in this field by appropriately considering the chemical nature of the analyte and the respective consequences for sampling and calibration.

While it will be extremely hard to obtain further samples from patients with a similar history, this study has provided us already with some very important information regarding the differences between intravenous and oral routes of exposure to GBCAs. Therefore, we are currently looking to develop further methods to study the stability of GBCAs under various environmentally relevant conditions and under conditions that GBCAs will be exposed to during their way through the body after oral uptake. First results appear to be promising, and we are very much looking forward to exciting, interdisciplinary future work together with colleagues from medical, biological, and industrial cooperation partners.

(1) P. Bücker, H. Richter, A. Radbruch, M. Sperling, M. Brand, M. Holling, V. Van Marck, W. Paulus, A. Jeibmann, and U. Karst, 

https://doi.org/10.1016/j.jtemb.2020.126665

Investigating Lanthanide Deposition Patterns in Tissue Using LA-ICP-MS Imaging

Nitrite poses a serious health risk because it is often present in drinking water, foods, biological systems, and agricultural products, and also acts as an environmental reagent for the production of highly carcinogenic N-nitrosamines upon interaction with proteins. Under mild conditions, tannic acid-protected fluorescence copper nanoclusters (TA-CuNCs) were found to be exclusively quenched in the presence of nitrite ions, and exhibited a good linear relationship with fluorescence intensity with a nitrite concentration within a 20–100 μM concentration window and a limit of detection of 40 nM. In addition, the mechanism associated with the sensitive fluorescence quenching response of nitrite with TA-CuNCs is discussed. The nanoprobe was used to detect nitrite in sausage, and the results were consistent with those obtained using UV-vis spectroscopy, which confirmed that the proposed method can be a rapid and reliable technique for detecting nitrite residues in real samples.

Nitrite represents a serious health-risk factor that often appears in biological, food, and environmental samples (1,2). Nitrite, in the form of sodium nitrite, is often added to meat products to maintain the red color and flavor of fresh meat while providing protection against microorganisms (3,4). The U.S. Environmental Protection Agency (EPA) defines the maximum levels of nitrite in drinking water and meat products to be 1 and 200 ppm, respectively (5). Nitrite is also one of the stable metabolites of nitric oxide, which is a messenger molecule involved in the regulation of numerous physiological and biological processes (6). Therefore, the illegal addition of nitrite to meat products and its potential harm to human health prompt the need for its sensitive detection, especially in commercial meat products. Therefore, a facile, effective, cost-effective, and sensitive method for nitrite detection needs to be developed urgently.

Various analytical methods, including chromatography (7,8), differential pulse voltammetry (9), capillary electrophoresis (10), electrochemical methods (11), and chemiluminescence methods (12), have been reported for nitrite detection. However, most of these methods are time-consuming or use toxic and environmentally unfriendly organic agents. Some of these analytical methods also require an elaborate detection process. To overcome these disadvantages, many organic molecules have been synthesized for use as fluorescent probes for sensitive nitrite detection (13,14). For example, noble metal (silver and gold) nanoclusters have been developed for trace determining of nitrite (15,16). Among the aforementioned techniques, fluorescence is well-suited, because of its sensitivity and simplicity. The fluorescence technique also satisfies the requirements of rapid nitrite screening.

Copper nanoclusters not only share similar characteristics with noble metal nanoclusters, such as fluorescence properties, particle size, and biocompatibility, but they are also inexpensive and stable (17–19). As a result, copper nanoclusters offer great potential as a nitrite-detection method that can potentially be superior to the current method of using noble metal nanoclusters (20–22). In particular, tannic acid-coated copper nanoclusters (TA-CuNCs) have attracted extensive scientific and technological interest because of their molecule-like properties, such as luminescence and unique charging properties (23,24). In this study, TA-CuNCs have been evaluated as fluorescent probes for nitrite detection and shown to possess novel and sensitive detection characteristics over a broad range of pH levels. The sensor, based on TA-CuNCs, was used to detect nitrite in commercially available sausage, illustrating potential practical applications.

Tannic acid was obtained from Sigma Aldrich. Sodium nitrite (NaNO

) was acquired from Beijing Chemical Co. All other chemicals agents were used directly. The water was purified through a Millipore purification system.

Fluorescence spectra were collected using a Shimadzu RF-5301PC fluorescence spectrophotometer. The excitation wavelengths were 360 nm for CuNCs.

UV-vis measurements were made on a Shimadzu UV-3600 spectrophotometer with 1 cm × 1 cm quartz cuvettes (4 mL volume) to determine nitrite content at a 520 nm wavelength. A simulated gastric fluid was mixed with NaCl and HCl. Then, 2 mL of 5 μg/mL sodium nitrite solution was added to 25 mL of simulated gastric fluid, and the mixture was incubated at 37 °C for 30 min. Afterwards, 2 mL of 0.4% sulfanilic acid and 1 mL of 0.2% naphthylamine were added to the mixture, which was then incubated at room temperature. The final volume of each mixture was adjusted to 50 mL.

Aqueous CuSO4 (0.2 mL, 0.1 M) and tannic acid solution (0.1 mL, 1 mM) with 20 mL water was stirred at room temperature. After 5 min, ascorbic acid solution (0.2 mL, 1 M) was added, and the mixture was incubated at 50 °C for 6 h. To remove all unreacted impurity, the product was extensively dialyzed against ultra-pure water for more than 24 h using a 3500 Da dialysis membrane, and the TA-CuNCs were freeze-dried to powder.

The extraction and clean-up procedure for nitrite in sausage was slightly modified from the previously reported investigation (25). For this procedure, a sausage sample (~25 to 50 g) was minced with a grinder and homogenized in a laboratory mixer for 3–5 min. Then, a 5 g portion was removed and extracted with saturated borax solution. Potassium ferrocyanide solution and zinc acetate solution were added to precipitate the protein, followed by 10 min of heating in a boiling water bath. The supernatant was then decanted and placed in another container.

CuNCs were stabilized with TA according to a previously described method (26). The optical properties of the TA-CuNCs were characterized by fluorescence and transmission electron microscopy (TEM). Figure 1a shows that at 360 nm excitation, the fluorescence spectrum of TA-CuNCs shows a strong band at 430 nm. As indicated from the inset of Figure 1a, the fluorescence lifetime of TA-CuNCs was 2.77 ns. The copper nanoclusters were highly dispersible and nearly spherical in shape with an average size of 2.3 nm (Figure 1b). The inset of Figure 1b suggests that the lattice fringes of the products are consistent with metallic copper and have a discerned lattice spacing of approximately 0.2989 nm. All these results suggest that the successful preparation of TA-CuNCs were consistent with the previous reports (27).

FIGURE 1: (a) Fluorescence excitation and emission spectra of TA-CuNCs; inset is the fluorescence lifetime of TA-CuNCs. (b) Photographs of TA-CuNCs in an aqueous solution under UV-vis light; inset is the transmission electron microscope (TEM) image of TA-CuNCs, showing single-magnified CuNCs.

Optimization of Conditions for Detecting Sodium Nitrite Using TA-CuNCs

We attempted to modify the conditions of the detection system with the aim of accurately detecting nitrite. The fluorescence intensities of TA-CuNC solutions in the presence of nitrite over the pH range of 3.0–10.0 are shown in Figure 2a. The visible fluorescence quenching occurred in the range of 4.0–8.0, but the fluorescence quenching caused by nitrite can be lower under the extreme pH conditions (strong alkali and strong acid). Thus, TA-CuNCs are able to detect nitrite under mild pH conditions. As shown in Figure 2b, no evident difference in the fluorescence quenching was observed at different reaction temperatures. At room temperature, nitrite was immediately detected after the nitrite was added. Therefore, it can be concluded that the content of nitrite can be detected under mild conditions.

FIGURE 2: Fluorescence spectra of TA-CuNCs with nitrite under (a) different pH, and (b) temperature.

Figure 3 shows that TA-CuNCs had a maximum emission peak at 430 nm. After adding nitrite to the TA-CuNC solution, the fluorescence intensity was quenched completely. A slight red shift of the emission peak was also observed, suggesting that the size or micro-environmental changes surrounding the copper core of TA-CuNCs are associated with the nitrite interaction.

FIGURE 3: Fluorescence spectra of TA-CuNCs (0.5 mg/mL) at pH 3.0 measured before and after the addition of different amounts of the nitrite (the content of sample was from 0 to 200 μM). Inset image shows (L to R) maximum to minimum fluorescence relative to concentration increase of nitrite, respectively.

Figure 4 shows that the degree of fluorescence quenching could be gradually intensified with the increased addition of the nitrite ion. The calibration plot revealed a good linear relation between the (

) of the system and nitrite concentration (Figure 4b). The regression equation was (

) = 15.6665C – 197.4892, with a typical detectable nitrite concentration range of 20–100 μM. The limit of detection was calculated to be 40 nM for nitrite when TA-CuNCs were diluted to 0.02 mg/mL. The relative standard deviation was 2.4% obtained from five replicate detections of 50 μM nitrite, indicating good reproducibility of the method.

 and the concentration of nitrite. Inset shows linear range for the relationship between 

 and the concentration of nitrite, from approximately 15 to 145 μM.

To test the selectivity of the developed method, we examined the influences of various metal ions and anions (the content of each substance was 50 μM) that may exist in sausage samples, including nitrate, magnesium, sodium, calcium, and potassium ions, as well as ascorbic and glutamic acids (Figure 5). The results indicate that all potentially interfering substances except nitrite had no obvious effect on the fluorescence changes of TA-CuNCs. Therefore, this fluorescence sensor exhibits good selectivity for nitrite and can be used to detect nitrite in real food and environmental samples.

FIGURE 5: The fluorescence intensity ratio (F/F0) of TA-CuNCs (0.5 mg/mL) in the presence of various interfering substances. Inset image shows corresponding vials of sample with respective interfering material.

To evaluate the practical application of TA-CuNCs as a fluorescence method for nitrite, the proposed technique was used to detect real samples. Sausage samples were analyzed after extraction and deproteinization. The Griess reagent method (UV-vis) for nitrite detection (28) was used to check the accuracy of the proposed method. The results of the two methods are listed in Table I. The fluorescence probe was found to have high accuracy, sensitivity, and precision, demonstrating the convenient and practical application of the proposed method for sensing nitrite analysis in real samples.

The fluorescence quenching process is actually a process by which the luminescence processes compete with each other to reduce the lifetime of the excited states of the luminescent molecules. Fluorescence quenching can be divided into static quenching and dynamic quenching, according to different quenching mechanisms. Dynamic quenching is produced by diffusion collision between the chromophore and quencher, during the fluorescence lifetime of the excited state. The quenching is caused by energy transfer or charge transfer. Static quenching is caused by a coordination reaction between the fluorescent molecules and fluorescent quencher molecules in the ground state, which results in a finite degree of binding. Structural complexes, which themselves cannot emit light, lead to fluorescence quenching of fluorescent molecules (29). To elucidate the mechanism of fluorescence quenching, the fluorescence temperature data were analyzed by the Stern-Volmer equation:

where the fluorescence intensity of TA-CuNCs with or without nitrite is 

 is quenching rate constant, and the fluorescent lifetime of TA-CuNCs is about 2.77 × 10

 s (see Figure 1). The concentration of the quenching agent is marked as [Q], and 

 at different temperatures (Figure 6 and Table II). There was a good linear relationship exhibited between 

/F and [Q]. Table II shows that the KSV value of TA-CuNCs and nitrite decreases with the increase of temperature, and the KSV is much smaller than the maximum diffusion collision quenching constant of biological macromolecules, which is 2.0 × 1010 L/mol x s. As a result, the possibility of dynamic quenching is increased, and the dissociation of the complexes formed often happens. Thus, the possibility of static quenching is reduced. It is more likely that the quenching of TA-CuNCs by nitrite ions involves a dynamic quenching process (30).

FIGURE 6: Stern-Volmer curves under different temperatures of TA-CuNCs (0.5 mg/mL) with nitrite.

Figure 7 shows that there was a good linear relationship between 

) and 1/[Q] as a function of temperature. The effective quenching constant 

 can be calculated from the modified Stern-Volmer equation, which is displayed in equation 2:

It can be seen from Table III that a good linear relationship exists, and that the 

 value decreases gradually with an increase in temperature. This trend is consistent with 

, which is further consistent with a quenching process that belongs to dynamic quenching. The thermodynamic parameters are listed in Table III. Δ

 < 0 indicate that nitrite and TA-CuNCs are Van der Waals forces or hydrogen bonding forces (31,32).

A quantitative and confirmatory method for the determination of trace levels of nitrite ion in sausage over a broad pH range was developed based on tannic acid-stabilized CuNCs (Scheme 1). In addition to the detailed exploration of the fluorescence quenching mechanism, the most efficient quenching of TA-CuNCs induced by nitrite was ascribed to a Van der Waals force or hydrogen bonding process. The methodology described was successfully utilized as a probe to detect nitrite ion in sausage, which was further confirmed using the Griess reagent method (UV-vis). The as-synthesized CuNCs are also suitable for future application in other foods because of their good sensitivity and low toxicity.

SCHEME 1: Schematic illustration of the fluorescence assay for nitrite using TA-CuNCs.

The present work was supported by the projects of NSFC (Nos. 21902058).

(1) M.J. Moorcroft, J. Davis, and R.G. Compton, 

(4) H.J. Ahn, J.H. Kim, C. Jo, H.S. Yook, and M.W. Byun, 

(5) United States Environmental Protection Agency, 

National Primary Drinking Water Regulations: Contaminant Specific Fact Sheets, Inorganic Chemicals 

(Consumer Version, Washington, DC, 2009).

(6) S. Moncada, R.M.J. Palmer, and EA. Higgs, 

(7) Y.T. Li, J.S. Whitaker, and C.L. McCarty, 

(8) L.J. He, K.G. Zhang, C.J. Wang, X.L. Luo, and S.S. Zhang, 

(9) H. Moshage, B. Kok, J.R. Huizenga, and P.L. Jansen, 

(10) F.D. Betta, L. Vitali, R. Fett, and A.C.O. Costa, 

(11) P. Wang, M.Y. Wang, F. Y. Zhou, G.H. Yang, L.L. Qu, and X.M. Miao, 

(12) J. Wu, X. Wang, Y. T. Lin, Y. Z. Zheng, and J. M. Lin, 

(13) B. Gu, L. Y. Huang, J.L. Hu, J.J. Liu, W. Su, X.L. Duan, H.T. Li, and S. Z. Yao, 

(14) Y. M. Shen, Q.J. Zhang, X.H. Qian, and Y.J. Yang, 

(15) C. Chen, Z.Q. Yuan, H.T. Chang, F.N. Lu, Z.H. Li, and C. Lu, 

(16) Q.L. Yue, L.J. Sun, T.F. Shen, X.H. Gu, S.Q. Zhang, and J.F. Liu, 

(17) J. Feng, Y.L. Chen, Y.X. Han, J.J. Liu, S.D. Ma, H.G. Zhang, and X.G. Chen, 

(18) A.L. Han, L. Xiong, S.J. Hao, Y.Y. Yanga, X. Li, G.Z. Fang, J.F. Liu, Y. Pei, and S. Wang, 

(19) N.D. Tan, J.H. Yin, Y.Q. Yuan, L. Meng, and N. Xu, 

(20) H.Y. Cao, Z.H. Chen, H.Z. Zheng, and Y.M. Huang, 

(21) Q. Tang, T.T. Yang, and Y.M. Huang, 

(22) H.B. Rao, W. Liu, Z.W. Lu, Y.Y. Wang, H.W. Ge, P. Zou, X.X. Wang, H. He, X.Y. Zeng, and Y.J. Wang, 

(23) Q. Liu, Q. Lai, N. Li, and X.G. Su, 

(24) R.S. Aparna, S.S. Syamchand, and S. George, 

(26) H.Y. Cao, Z.H. Chen, H.Z. Zheng, and Y.M. Huang, 

(27) X.L. Cao, X. Li, F.X. Liu, Y.N. Luo, and L.Y. Yu, 

(30) H.S. Geethanjali, D. Nagaraja, R.M. Melavanki, and R. A. Kusanur, 

(31) C.Q. Jiang, M.X. Gao, and X.Z. Meng, 

 are with the College of Chemical and Pharmaceutical Engineering, at the Jilin Institute of Chemical Technology, in Jilin City, in the People’s Republic of China. 

 is with Jilin Petrochemical Company, in Jilin City, in the People’s Republic of China. Direct correspondence to: 

Nitrite poses health risks. This study evaluates the results of using tannic acid- protected fluorescence copper nanoclusters (TA-CuNCs) to detect nitrite in food.

A Facile Synthesis of Tannic Acid–Protected Copper Nanoclusters and the Sensitive Fluorescence Detection of Nitrite Ion Under Mild Conditions

Howard Mark serves on the Editorial Advisory Board of 

 and runs a consulting service, Mark Electronics that provides assistance, training, and consultation in near-IR spectroscopy as well as custom hardware and software design and development.

Our annual review of products introduced during the past 12 months, along with an assessment of the overarching trends.

We are pleased to present our annual review of new products. As has been the case for many years now, this annual review includes products launched not only at the annual Pittsburgh conference (“Pittcon”), but also throughout the preceding year.

Nevertheless, Pittcon remains an important source of new product announcements. This year’s Pittcon, however, was held online—a first for the event—because of the Covid-19 pandemic. In the online format, you could attend technical presentations, keynote talks, short courses, workshops, and networking sessions, as well as see exhibitor demonstrations, attend the employment bureau, and—related to our interests and purposes here—you could visit exhibits and talk to exhibitor representatives. The main difference this year was that we couldn’t unexpectedly run into old friends while traversing the halls or aisles. We also could not participate in a “hands-on” demonstration of equipment.

Presumably because of the online format, there was a decrease in the size of the exposition this year (only 179 exhibitors, compared to 787 last year) and the absence of several large vendors. This year, again presumably because of the online format, no product awards were given out.

There was a significant change in attendance at the conference compared to previous years, but we have to acknowledge that we are comparing the “apples” of a live conference with the “oranges” of an online one. The overall attendance in 2020 was 12,841 registered participants. Although it was clear from the live attendance numbers visible in the online platform for this year’s event that the numbers were comparatively quite small this year, generally around 1000 at any given time, official attendance figures for 2021 were not available by our deadline. Because most features of the conference are available on demand through June 12, the conference organization will not have final numbers until then.

The review that follows is categorized by wavelength region or type of spectroscopy. This arrangement is designed to allow readers to compare instruments from different manufacturers, although this process sometimes compares handhelds and other portable instruments with high-end benchtop research tools. Our included categories fluctuate from year to year, depending on trends in new product launches. The categories appearing in this year’s review are:

Mid-infrared (Mid-IR) and terahertz (THz) spectroscopy

Near infrared (NIR) spectroscopy Raman spectroscopy

As we have reported in previous reviews, manufacturers have recently been producing instruments that incorporate two or more different, and sometimes disparate, technologies. Given that the number of such instruments has been increasing every year, we considered whether a new approach to this question was warranted. Ultimately, we decided to assign a primary category for each product, but also list potential alternate categories that the product might plausibly be listed under. For an ICP-MS instrument, for example, which could plausibly fit under either the “Atomic Spectroscopy” (for the ICP) or the “Mass Spectrometry” category, we have assigned it to the Atomic Spectroscopy category, but in that table, we show the secondary category in parentheses, in the left-hand column, below the company name, like this:

We also employed a similar label for accessories, indicating the primary technology that the accessory is intended for in parentheses.

As in the past, accessories are tools used in conjunction with an instrument, such as sample preparation or attenuated total reflectance (ATR) devices, whereas components, such as lasers or detectors, are used within an instrument. Yet no matter how we present them, there are always marginal cases, such as where a product is so large and integral to the operation of the analytical system that it is unclear where the concept of an “accessory” ends and an “instrument” begins.

For all of these reasons, even the manufacturer is sometimes unsure about what category a given device belongs to. Sometimes, the distinction depends on the perspective of the observer. An example of this is gas chromatography–infrared spectroscopy (GC–IR). From the point of view of the spectroscopist, the GC is “simply” a very sophisticated sample preparation accessory, although from the point of view of the chromatographer, the spectrometer is “merely” a very complicated detector!

The software category includes programs for instrument control, data collection, and data processing, as well as products for storage and transmission of data. The category also includes collections of data, such as databases (libraries) of spectra, as well as collections of calibration models used in conjunction with the still developing field of chemometric algorithms that analyze the data.

As is our custom, Table I lists the categories that the various companies offer instruments in.

Typically, our vendor surveys answer our question about trends in many different ways. The 2021 surveys, however, show a consistent observation about the importance of speed and efficiency. Although similar to comments given over many years, this theme was more noticeable in 2021. Many laboratories downsized or worked with limited staffing in the last year, requiring those who remained to be more productive. Further, as older subject matter experts (SMEs) retired, they were either not replaced or were replaced with less-experienced workers who had little time to gain the benefit of the SMEs’ experience. In addition, those on-site workers were often present in shorter shifts or limited days, as well as performing a lot of remote work, meaning they had to plan and execute their analyses carefully.

These variables resulted in instrument specifications growing more aggressive, with requirements like more automation, intense sources, higher signal-to-noise (S/N), and more-sensitive detectors, resulting in faster data collection. Also, software (particularly the offline analytical type) became even more prominent in instrument sales. Finally, virtual training (both general webinars and instrument-specific training on operations) became very important. Even vendors who did not specifically mention the “faster, more efficient” theme implied this through their product descriptions.

We do not expect this trend will change, even if more people return to the physical workplace for longer hours. The “need” to work at home experienced during the pandemic has transitioned to the “ability” to work at home (as a viable work option, irrespective of need), through various other sharing platforms. Many instruments can now be operated remotely, with autosamplers enabling unattended throughput. Laboratory staff need to be physically present only long enough to set up a batch and start the process; they can then monitor and tweak the process remotely. Even academic teaching laboratories are reaping the benefits of remote instrumentation, because students can now check the progress of a measurement from the library or their dorm rooms.

Another outgrowth of the loss of SMEs has been the emphasis placed on digital science and, more specifically, machine learning. Broadly, this tool enables a system (instrument plus computer plus software) to derive relationships between data and answers that can be reproduced in the absence of human intervention, enabling the system to make “intelligent” decisions about specific characteristics of a sample, such as its usability in a specific application, or an identification based on large datasets. We feel strongly this will be a key driver in the future workspace as the machine learning algorithms improve and become more broadly applicable (consider how online shopping proposes new things based on your past choices; the same logic can be applied to a production process).

We see fewer application-specific analyzers appearing this year, although some fields, like cannabis and microplastics, are attracting attention. In many cases, existing tools are being combined with new software to address these fields, such as the innovations from multiple vendors implementing microplastics analysis onto Raman, FT-IR, and quantum cascade laser (QCL)–based microscopy systems.

Handhelds and portables continue to appear, but not with the same ubiquity as a few years back when we noted every aisle at Pittcon seemed to have a handheld Raman or NIR tool on display. Many articles have appeared in the literature, and in this journal specifically, about the benefits of the handhelds and portables. There has been less discussion about the performance differential between handheld and laboratory instruments; however, this difference is largely driven by the different purposes and applications of the two types of instruments (“What is this pile of white powder? Is it dangerous?” versus “I need to analyze a tiny defect in a sheet of polymer or discolored flecks in an otherwise homogeneous product”).

Below, we highlight new introductions in each product category. Individual tables provide more detail for the products mentioned. Table I contains the index of companies and the categories where their products appear.

See Table II for more information about atomic spectroscopy instruments.

Cubert GmbH demonstrated the Ultris X20, a UV–vis-NIR imaging spectrometer and hyperspectral snapshot camera capable of capturing a hyperspectral image (x, y, lambda) at very high resolution within a millisecond. Cubert GmbH’s product could also fit into the “UV-vis” and “NIR” categories.

Greateyes had two products on display: Alex, a low-noise charged-coupled device (CCD) camera series of highly sensitive, cooled cameras with vacuum flange equipped with ultralow noise 18-bit readout electronics for imaging applications in the vacuum ultraviolet (VUV), extreme ultraviolet (EUV), and X-ray range up to 20 keV; and ELSE, a low noise CCD camera that integrates cutting-edge low-noise electronics and ultra-deep cooling technology. The Greateyes products could also apply to the “X-Ray” category.

Monstr Sense Technologies, LLC showed Bigfoot, with ultrafast optics and radio-frequency electronics to extract weak ultrafast signals from strong excitation background light. Bigfoot could also be included in the “Raman spectroscopy” category.

Nanobase, Inc. introduced the XperRF, a hybrid Raman spectroscopy microscope instrument and a transmission spectrometer for >90% spectrum peak efficiency. This product could also fall into the “UV-vis” and “Raman spectroscopy” categories.

Pembroke Instruments, LLC introduced the SWIR-200, a short-wavelength infrared (SWIR) microscope featuring a flexible design supporting a wide range in the field of view, magnification, and working distance to the sample. This product could fall into the “NIR” category.

Princeton Infrared Technologies, Inc. showed a 2nd-generation 1280 SciCam, an InGaAs SWIR camera that is the only International Traffic in Arms Regulations (ITAR)-free 1.3 MegaPixel-cooled SWIR camera that exhibits high photo response uniformity and low dark current.

Our annual review of new products for atomic and molecular spectroscopy, including details by category and highlights of overarching trends.

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