ISC Environmental Session Highlights Separation and Analysis of Pollutants

Chromatography plays a vital role in environmental analysis by helping address some of the most pressing issues related to pollutants.

This was underscored during the 34th International Symposium on Chromatography, where scientists from around the world presented the latest advancements in the field. One of the standout presentations came from Jackie Mosely, a senior lecturer in mass spectrometry at the University of York, U.K. Mosely’s team has been investigating the potential of the microorganism B. humi to produce biosurfactants from waste fruits and vegetables—an approach for bioremediation in polluted regions. Originally isolated from the heavily contaminated Niger Delta, B. humi was tested on eight locally available carbon sources to evaluate its potential for environmental cleanup.

Wooden boats on Niger River: © Katya Tsvetkova- stock.adobe.com

Oil pollution in the Niger Delta has been a persistent issue, with an estimated 1.9 million barrels of oil spilled between 1976 and 1996, causing long-term damage to the ecosystem. In her presentation, Mosely detailed how her team cultivated B. humi on substrates such as red apple, banana, banana skin, raspberries, strawberries, kiwi, carrots, and cabbage to assess biosurfactant production. Using techniques like matrix-assisted laser desorption ionization coupled with tandem mass spectrometry (MALDI MS/MS) and liquid chromatography tandem mass spectrometry (LC MS/MS), they identified complex mixtures of biosurfactants.

Initial findings showed that different substrates led to the production of homologous series of cyclic lipopeptides, which varied in acyl chain length, amino acid composition, and sequence, belonging to the iturin, fengycin, and surfactin families. Banana fruit was a particularly good producer of biosurfactants, Mosely noted. While MALDI-MS provided a rapid screening method, she emphasized that careful desalting is essential for accurate results.

Analyzing Microplastic-Associated Chemicals in Marine Environments

In another presentation, Lucy Howarth-Forster from the University of Plymouth, U.K., explored the complex issue of microplastic-associated chemicals in marine environments. She highlighted the “wild west” nature of the plastics industry, where the chemical compositions of plastics are often unknown, complicating environmental risk assessments. Microplastics and plastic debris not only accumulate a wide array of additives, including plasticizers, flame retardants, and UV stabilizers, but also act as carriers for harmful chemicals that can leach into the marine ecosystem, posing significant threats to aquatic life.

To address these concerns, Howarth-Forster and her team utilized comprehensive multidimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-ToF-MS) to analyze chemical extracts and leachates from both conventional plastics (polyethylene, polypropylene, PET, and PVC) and biodegradable polymers (PLA, PBS, PBAT, and PHBV). The team prepared extracts using ultrasonic-assisted extraction in organic solvents and simulated the environmental conditions of seawater and gut fluids to produce leachates. By characterizing both extracts and leachates, they provided a clearer picture of the fate of plastic-associated chemicals. This approach offers enhanced separation capabilities compared to traditional one-dimensional methods, making it a powerful tool for isolating and identifying priority pollutants from microplastics.

“These plastics are acting as vectors for these chemicals into the environment,” Howarth-Forster said, underscoring the need for better understanding and regulation of microplastic pollutants.

Determining PFAS in the Environment Using GC

The final presentation of this session was delivered by Flavio Antonio Franchina of the University of Ferrara in Italy. Franchina spoke about the feasibility of combining GC/GC×GC and MS for the determination of poly- & perfluorinated hydrocarbons in environmental applications.

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals commonly used in consumer products and industrial applications due to their unique properties. Chemically, they consist of a carbon chain bonded to multiple fluorine atoms, making them highly stable and versatile. Some PFASs, particularly those that are neutral and volatile, have gained increased attention from environmental agencies because they can be released into the air from household products and are detectable in the atmosphere. Despite their relatively high molecular weights (over 600 Da), PFAS compounds are more volatile than non-fluorinated analogs due to the weak van der Waals interactions between the fluorine atoms, making them suitable for analysis using GC-MS.

Franchina’s team developed a parallel GC and GC×GC methodology coupled with low- and high-resolution time-of-flight mass spectrometry (TOF-MS) for analyzing (semi)volatile PFAS, including fluorotelomer alcohols (FTOH), acrylates (FTAc), and alkyl sulfonamide derivatives (N-MeFOSA, N-EtFOSA, N-MeFOSE, and N-EtFOSE). Different ionization techniques—electron impact, positive chemical ionization, and negative chemical ionization—were used to study the spectra of these targeted chemicals. Dynamic headspace extraction was employed for air sampling, using the most suitable adsorbent material for selectivity and sensitivity. The extraction method was optimized based on sampling volume and adsorbent type, using a mix of PFAS standards and various spiked household goods and environmental samples, such as air, water, and soil.