"Inside the Laboratory" is a joint series with LCGC and Spectroscopy, profiling analytical scientists and their research groups at universities all over the world. This series spotlights the current chromatographic and spectroscopic research their groups are conducting, and the importance of their research in analytical chemistry and specific industries. In this edition of “Inside the Laboratory,” Lee Blaney of the University of Maryland Baltimore County (UMBC) discusses his laboratory’s work with using liquid chromatography (LC) techniques to analyze and measure contaminants of emerging concern (CECs) in water, soil, and environmental samples.
Environmental analysis is a field where chromatography plays an integral role. Detecting, identifying, and quantifying per- and polyfluoroalkyl substances (PFAS) and contaminants of emerging concern (CECs) are currently hot topics in environmental analysis, mostly because it affects both the environment and natural resources humans regularly use. Chromatographic techniques like liquid chromatography coupled to tandem mass spectrometry (LC–MS/MS) offer unparalleled sensitivity and specificity in separating and identifying PFAS within complex matrices, such as water, soil, and biological samples. Through chromatographic separation, PFAS are eluted based on their unique physicochemical properties, allowing accurate and precise quantification by downstream detectors. This analytical approach not only aids in assessing environmental contamination, but also contributes significantly to understanding the exposure pathways and potential health risks associated with PFAS.
Dr. Lee Blaney is a Professor and Associate Director of Sustainability Engineering at the University of Maryland Baltimore County. He received his BS and MS in Environmental Engineering at Lehigh University before completing his PhD in Civil Engineering at the University of Texas at Austin. His laboratory is primarily focused on studying CECs, including developing advanced analytical methods that can better improve detection and quantification of CECs in the environment, as well as developing new treatment technologies for diverse contaminants in water and wastewater.
Recently, LCGC International spoke to Dr. Blaney about his laboratory’s work with PFAS and CEC analysis, as well as the current research projects they are working on.
Can you tell me about the research that your laboratory group is working on currently?
Most of our research involves contaminants of emerging concern (CECs), such as pharmaceuticals, hormones, and personal care products. These are chemicals that we use every day to improve our quality of life, but we don’t really think about them as “pollution." Nevertheless, every chemical that we use ultimately makes its way into the aquatic environment, where it can have unintended consequences. When we take an antibiotic to fight an infection, some fraction of the antibiotic gets excreted into our toilets without undergoing any chemical changes. Wastewater treatment plants were not designed to remove pharmaceuticals, causing antibiotics to be discharged into the environment, where they can accelerate the development and spread of antimicrobial resistance. Similar concerns abound for other CECs. For this reason, our group focuses on developing (i) new analytical methods to measure CECs in the aquatic environment and (ii) new treatment technologies to ensure CEC removal from both drinking water and wastewater.
In the research that you and your group does, what particular analytical techniques do you normally use?
Our laboratory primarily employs liquid chromatography (LC) coupled to ultraviolet (UV), fluorescence (FL), and triple quadrupole tandem mass spectrometry (MS/MS) detectors. Some CECs have strong absorbance and/or fluorescence properties that allow us to measure their concentrations using high performance liquid chromatography (HPLC) with UV or FL detection in relatively clean samples, such as those produced during laboratory experiments. However, real environmental samples contain dozens of CECs at concentrations of 1–1000 ng/L (that is, 1–1000 parts per trillion). Real samples also contain much higher concentrations of natural organic matter and background ions. With appropriate pretreatment via solid-phase extraction, we can not only concentrate the analytes, but also remove some of the interfering substances. Nevertheless, the large number of CECs in real samples mandates the use of LC–MS/MS, which can concurrently measure analytes with similar retention times. During LC–MS/MS analysis, we have several analytical criteria that ensure highly selective and sensitive measurement of each CEC. In particular, we need to match the LC retention time of our chemical standards for each CEC, produce the same MS-1 ion during electrospray ionization, and generate the same MS-2 ions for analyte quantitation and confirmation by the triple quadrupole MS/MS detector. The fast scan times of the MS/MS detector allow us to measure dozens of CECs in the same method. These aspects make LC–MS/MS the go-to technology for environmental analytical chemists and engineers studying CECs.
What’s the difference between CECs and PFAS?
Contaminants of emerging concern is an umbrella term for all contaminants that have been identified as having potentially harmful effects on the environment or humans. The “emerging” concern means that we do not yet fully understand the toxicity of these chemicals in the environment or people. Per- and polyfluoroalkyl substances (PFAS) are a class of almost 15,000 fluorinated chemicals used in fire-fighting foams, nonstick cookware, fast food wrappers, and many other industrial and consumer products. Even though there are many PFAS, you can consider them to be a subcategory of CECs. Due to the chemical and thermal stability of the carbon-fluorine bonds in PFAS, these chemicals do not readily degrade during wastewater treatment or in the environment. In the last few years, we have learned about a number of harmful outcomes of PFAS in humans. As a result, new drinking water regulations were recently approved for six PFAS in drinking water. In a sense, some PFAS have therefore transcended the concept of “contaminants of emerging concern” and have just become “regulated contaminants." The new regulations for PFAS will also spur the growth and development of analytical contract labs to meet the demand for regular analysis of PFAS in drinking water across the country.
Going back to LC–MS methodologies, are there any limitations of using that technique right now that are kind of preventing you and your group from figuring some things out in your research or?
The biggest limitation is the large number of CECs. Right now, we are only measuring a small fraction of the specialty chemicals employed in everyday life. For example, our lab has developed methods for dozens of antibiotics, but each of those compounds undergo chemical transformations in natural and engineered systems. These reactions produce several unknown transformation products that may still retain antimicrobial properties. Without chemical standards, it is difficult to employ targeted LC–MS/MS methods to measure these transformation products. As another example, the latest EPA method measures 40 PFAS, which accounts for less than 1% of the estimated 15,000 PFAS. If we extrapolate this issue across the full suite of CECs, the number of individual chemicals becomes staggering. For this reason, we have prioritized certain chemicals that represent the most concern, but new approaches will be needed in the future to best safeguard environmental and public health.
With all the advancements that are going on in with the techniques and the technologies, how does you and your group stay on top of all the developments going on in this space?
We regularly go to conferences and meetings focused on the latest developments in CEC analysis. Several of our current projects are funded by the Strategic Environmental Research and Development Program (SERDP), which holds regular meetings for PFAS-related research. These conferences and meetings are great opportunities to share our work, receive feedback, learn about the work of other groups, and share notes to advance knowledge in the environmental analytical chemistry and environmental engineering fields. In addition, I serve as an executive editor at the Journal of Hazardous Materials. While it is a demanding job to keep up with all the manuscripts submitted by authors, this role also gives me a chance to read the latest work from around the world to learn about the latest updates and findings.
Are there any upcoming research projects on your end that you’re excited about?
Our best available technologies for PFAS treatment work well for long-chain PFAS, such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), which contain eight carbon atoms in their chemical structures. Short- and ultrashort-chain PFAS, which contain less than eight carbons, pose challenges to conventional treatment technologies. Many of these compounds are also not included in current analytical methods. Our new SERDP project will focus on developing novel hybrid anion-exchange resins to remove these challenging contaminants from water. We’re excited about our materials and the promising preliminary data, and we’ll look forward to sharing our findings with the environmental community to continue to address the challenges associated with PFAS treatment and remediation.
This interview has been edited for clarity.
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