This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Halogenated organic compounds (HOCs) are widely used in industrial and consumer products, but some are highly persistent and difficult to analyze and manage. In a new study, researchers developed an innovative approach for carbon isotope ratio analysis of these compounds, which has previously been difficult.
This approach will help track the sources and environmental pathways of such pollutants, contributing to the development of effective management strategies. Halogenated organic compounds (HOCs) have been used in a wide range of products, including disinfection by-products (DBPs), pesticides, refrigerants and industrial chemicals. Because of their persistence, tendency for bioaccumulation and toxicity, HOCs have been recognized as contaminants of global concern.
HOC exposure has been implicated in several health effects in humans. For example, haloacetic acids, a major class of DBPs, have been reported to increase the risk of bladder cancer. Perfluoroalkyl and polyfluoroalkyl substances, including trifluoroacetic acid, are another class of persistent HOCs that are highly resistant to degradation.
Conventional approaches for environmental monitoring mainly rely on concentration measurements and offer limited information about pollution sources and environmental transformation processes. An effective approach for uncovering environmental behavior is carbon isotope analysis, traditionally conducted using gas- or liquid chromatography–isotope ratio mass spectrometry (GC-IRMS and LC-IRMS, respectively). Carbon isotope ratios (δ¹³C) can provide information about the origin and production history of chemicals, as even the same compound can have different δ¹³C values depending on its production process.
Indeed, δ13C analysis has been reliably used to detect food fraud. However, δ13C analysis of HOCs containing strong carbon–chlorine or carbon–fluorine (C–F) bonds remains challenging because their oxidation is difficult under conventional LC-IRMS combustion conditions, where oxidation is carried out near 99°C. To address this challenge, a research team led by Professor Hiroto Kawashima from the Department of Bioscience and Engineering, College of Systems Engineering and Science at Shibaura Institute of Technology (SIT), Japan, in collaboration with researchers from the National Institute of Advanced Industrial Science and Technology (AIST), Japan, developed an innovative interface capable of high-temperature, high-pressure combustion, enabling accurate and precise δ¹³C analysis of several halogenated compounds.
"We developed a custom-built high-temperature, high-pressure combustion interface for LC-IRMS," Kawashima explains. "This unique system enables stable carbon isotope analysis of a wide range of halogenated compounds, providing a new tool for source identification and fate analysis." The team included Sota Maehara from SIT and Dr. Sachi Taniyasu from AIST.
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