A Novel Platform for Molecular and Elemental Trace Analysis of Environmental Microplastics at Single Particle Resolution

• Applicant: Dr. Matthias Elinkmann
• Subject Area: Analytical Chemistry
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 569759298

Plastic waste is becoming a critical ecological hazard all over the world. Especially the smallest plastic particles (nano- and microplastic particles, NMPs) pose a serious risk to humans and the environment, as NMPs are persistent, mobile and bioavailable. A precise understanding of the exposure to NMPs is not accessible due to limitations of existing analytical methods. In particular, there is a lack of techniques that analyze aqueous suspensions with high sample throughput and sound specificity in terms of polymer composition and particle size. In addition, NMPs are subject to severe ageing processes in the environment due to oxidation and UV radiation. These processes change key properties such as size and functional groups of the polymer backbone. As a result, aged NMPs tend to adsorb and accumulate other pollutants from the environment, with research interest focusing in particular on heavy metals. This adds an elemental analytical component to the analytical question. The project has the goal of establishing a new analytical platform for the characterization of microplastics in the environment based on two orthogonal techniques. The platform is able to characterize the polymer and trace element composition, size, number and ageing degree of NMPs on a single particle basis. The first component is a completely new technique called optofluidic force induction (OF2i). It can trap NMPs from aqueous suspensions in a special vortex laser beam and characterize them using light scattering. This unique method not only records particle size and number but also generates Raman spectra from the inelastically scattered light component to identify polymer species. A key innovation is to combine OF2i directly with inductively coupled plasma-time-of-flight mass spectrometry (ICP-TOFMS). Thanks to recent innovations, this allows to determine elemental mass fractions spectrally and on a single particle basis (spICP-MS). This new type of hyphenation provides quantitative data on the essential particle parameters on a large scale and as non-target analysis for the first time. The project divides method development into three phases. First, both techniques are optimized for the analysis of NMPs. Subsequently, a microfluidics-based interface will be implemented to transfer particles between the instruments without losses. In parallel, algorithms will be developed to correlate Raman and ICP-TOFMS data for individual particles. In the third phase, heavy metal uptake of NMPs will first be investigated with particles aged by ozonation. Subsequently, river water samples from the Mur (Styria, Austria) will be taken at the effluents of wastewater treatment plants in order to comprehensively characterize environmentally relevant NMPs using OF2i-Raman-spICP-TOFMS for the first time.

• DFG Programme: WBP Fellowship
• International Connection: Austria
• Host: Professor Dr. David Clases