Open Access

Deuterated polystyrene (D-PS) improves microplastic detection with TED-GC / MS, among other things through higher reproducibility. It is inexpensive (0.1 ct / analysis) and can be dosed quickly and reproducibly thanks to its good solubility (e.g. in toluene). However, certain matrices lead to an exchange of the deuterium with hydrogen. The poster shows the measuring principle, in which matrices H/D-exchange takes place, the results of kinetic studies and ways of preventing or circumventing the H/D-exchange.

In this study, carried out within the Joint Danube Survey 4, a comprehensive microplastic screening in the water column within a large European river basin from its source to estuary, including major tributaries, was realized. The objective was to develop principles of a systematic and practicable microplastic monitoring strategy using sedimentation boxes for collection of suspended particulate matter followed by its subsequent analysis using thermal extraction desorption-gas chromatography/mass spectrometry. In total, 18 sampling sites in the Danube River Basin were investigated. The obtained suspended particulate matter samples were subdivided into the fractions of >100 μm and <100 μm and subsequently analyzed for microplastic mass contents. The results showed that microplastics were detected in all samples, with polyethylene being the predominant polymer with maximum contents of 22.24 μg/mg, 3.23 μg/mg for polystyrene, 1.03 μg/mg for styrene-butadiene-rubber, and 0.45 μg/mg for polypropylene. Further, polymers such as different sorts of polyester, polyacrylates, polylactide, and natural rubber were not detected or below the detection limit. Additional investigations on possible interference of polyethylene signals by algae-derived fatty acids were assessed. In the context of targeted monitoring, repeated measurements provide more certainty in the interpretation of the results for the individual sites. Nevertheless, it can be stated that the chosen approach using an integrative sampling and determination of total plastic content proved to be successful.

The terminal settling velocity is considered the most critical parameter determining the transport of tire and road wear particles (TRWP) in aquatic environments. Nonetheless, no respective empirical data has been reported so far. In this study, particle samples from a road simulator and a highway tunnel were investigated with a validated imaging method. Different density and size fractions of both samples were measured separately, acquiring sizes and settling velocities of more than 30,000 individual particles. In addition, tire marker polymers were analyzed for each fraction via thermal extraction desorption-gas chromatography/mass spectrometry. Finally, the acquired particle data was combined according to the fractions’ estimated tire contents in order to deduce detailed probability distributions of particle size and settling velocity for the actual TRWP from both samples. Weighted by TRWP-incorporated tire mass, median diameters of 54 and 44 μm as well as median settling velocities of 0.65 and 0.22 mm/s were found for TRWP from the road simulator and highway tunnel, respectively. This study thus provides the first ever empirical data on TRWP settling velocities in water, which can be highly valuable input for modeling the environmental transport of TRWP and for dimensioning TRWP retention systems.

Introduction to microplastics, definition, relevance, analytical approaches & challenges. TED-GC/MS working principle, features & performance. Optimisation in TED-GC/MS methodology, new validation data. Replacement of Internal Standard, outlook towards upcoming publication and application within EU´s revised drinking water directive.

In the talk, the BAM is introduced and the motivation for our engagement in the field of microplastic analysis is explained. The challenges in the analysis of microplastics are shown and how we deal with them. The working principle of TED-GC/MS and its performance parameters are presented, as well as the procedure for identifying and quantifying polymers in environmental samples. Interesting results are shown using selected examples. Finally, BAM's microplastic reference materials are highlighted.