New Method Enables Analysis of Polycyclic Aromatic Hydrocarbons in Plastics Production Intermediates

A team of researchers from the Institut für Umwelt & Energie in Duisburg, Germany, has developed a new method to detect and quantify polycyclic aromatic hydrocarbons (PAHs) in intermediates used in plastics production. The study, published in the Journal of Separation Science, presents a generic liquid chromatography column switching approach that enables the analysis of 18 PAHs listed by the Environmental Protection Agency and the European Union (1).

While regulations such as European Union No. 1272/2013 exist to control the concentration of PAHs in plastic end products, the same level of scrutiny is not applied to intermediate substances. To address this gap, the researchers devised a comprehensive method for analyzing PAHs in plastics production intermediates.

The method relied on direct large volume injection from solutions of plastic additives, followed by liquid chromatography coupled to fluorescence detection. The team used three specific additives, namely Irganox 1010, ureido methacrylate, and cetyl methacrylate 1618F, as examples during method development.

By utilizing two serially coupled columns connected by an intermediate valve, the researchers were able to remove matrix interferences on the first column and separate the analytes on the second column. The valve played a crucial role in diverting the matrix after the first column and introducing water upstream of the second column using an additional pump. This allowed for the concentration of samples in aqueous or organic media at the column head.

The method demonstrated high sensitivity, with a limit of detection below 1 ng/mL for 15 PAHs when employing a 100 μL injection volume and online aqueous dilution of 1:3. Furthermore, the researchers identified concentrations ranging from 1.6 to 10.3 ng/mL for the three plastic additives tested.

This innovative approach provides a valuable tool for analyzing PAHs in plastics production intermediates, bridging the gap in regulatory oversight and ensuring the comprehensive evaluation of potential PAH contaminants throughout the manufacturing process. By expanding our understanding of PAH distribution and levels in plastic additives, this method contributes to the ongoing efforts to monitor and mitigate environmental and human health risks associated with these compounds.

As further research and validation of the method are conducted, it holds the potential to be applied in various industrial settings, aiding in the assessment and control of PAH contamination and supporting the development of safer and more environmentally sustainable plastic materials.

Reference

(1) Kochale, K.; Thissen, J.; Cunha, R.; Lamotte, S.; Teutenberg, T.; Schmidt, T. C. Enrichment and quantification of 18 polycyclic aromatic hydrocarbons from intermediates for plastics production by a generic liquid chromatography column switching. J. Sep. Sci. 2023. DOI: https://doi.org/10.1002/jssc.202300076