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Veröffentlichung Microplastic analysis using chemical extraction followed by LC-UV analysis: a straightforward approach to determine PET content in environmental samples(2020) Müller, Axel; Goedecke, Caroline; Eisentraut, Paul; Braun, UlrikeBackground The ubiquitous occurrence of microplastic particles in marine and aquatic ecosystems was intensively investigated in the past decade. However, we know less about the presence, fate, and input paths of microplastic in terrestrial ecosystems. A possible entry path for microplastic into terrestrial ecosystems is the agricultural application of sewage sludge and solid bio-waste as fertilizers. Microplastic contained in sewage sludge also includes polyethylene terephthalate (PET), which could originate as fiber from textile products or as a fragment from packaging products (foils, bottles, etc.). Information about microplastic content in such environmental samples is limited yet, as most of the used analytical methods are very time-consuming, regarding sample preparation and detection, require sophisticated analytical tools and eventually need high user knowledge. Results Here, we present a simple, specific tool for the analysis of PET microplastic particles based on alkaline extraction of PET from the environmental matrix and subsequent determination of the monomers, terephthalic acid, using liquid chromatography with UV detection (LC-UV). The applicability of the method is shown for different types of PET in several soil-related, terrestrial environmental samples, e.g., soil, sediment, compost, fermentation residues, but also sewage sludge, suspended particles from urban water management systems, and indoor dust. Recoveries for model samples are between 94.5 and 107.1%. Limit of determination and limit of quantification are absolute masses of 0.031 and 0.121 mg PET, respectively. In order to verify the measured mass contents of the environmental samples, a method comparison with thermal extraction-desorption-gas chromatography-mass spectrometry (TED-GC/MS) was conducted. Both methods deliver similar results and corroborated each other. PET mass contents in environmental samples range from values below LOQ in agriculture soil up to 57,000 mg kg-1 in dust samples. Conclusions We demonstrate the potential of an integral method based on chemical extraction for the determination of PET mass contents in solid environmental samples. The method was successfully applied to various matrices and may serve as an analytical tool for further investigations of PET-based microplastic in terrestrial ecosystems. © The Author(s) 2020Veröffentlichung Decomposability versus detectability: First validation of TED-GC/MS for microplastic detection in different environmental matrices(2023) Kittner, Maria; Eisentraut, Paul; Braun, UlrikeA fast method for microplastic detection is thermal extraction desorption-gas chromatography/mass spectrometry (TED-GC/MS), which uses polymer-specific thermal decomposition products as marker compounds to determine polymer mass contents in environmental samples. So far, matrix impacts of different environmental matrices on TED-GC/MS performance had not yet been assessed systematically. Therefore, three solid freshwater matrices representing different aquatic bodies with varying organic matter contents were spiked with a total of eight polymers. Additionally, for the first time, the two biodegradable polymers polybutylene adipate terephthalate (PBAT) and polylactide (PLA) were analysed using TED-GC/MS. The methodological focus of this work was on detectability, quality of signal formation as well as realisation of quantification procedures and determination of the limit of detection (LOD) values. Overall, TED-GC/MS allowed the unambiguous detection of the environmentally most relevant polymers analysed, even at low mass contents: 0.02wt% for polystyrene (PS), 0.04wt% for the tyre component styrene butadiene rubber (SBR) and 0.2wt% for polypropylene (PP), polyethylene (PE) and PBAT. Further, all obtained LOD values were increased in all matrices compared to the neat polymer without matrix. The LOD of the standard polymers were increased similarly (PS: 0.21-0.34 (micro)g, SBR: 0.27-0.38 (micro)g, PP: 0.32-0.36 (micro)g, PMMA: 0.64-1.30 (micro)g, PET: 0.90-1.37 (micro)g, PE: 3.80-6.99 (micro)g) and their decompositions by radical scission processes were not significantly influenced by the matrices. In contrast, matrix-specific LOD increases of both biodegradable polymers PBAT (LOD: 1.41-7.18 (micro)g) and PLA (0.84-20.46 (micro)g) were observed, probably due to their hetero-functional character and interactions with the matrices. In conclusion, the TED-GC/MS performance is not solely determined by the type of the polymers but also by the composition of the matrix. © 2023 Wiley VCH GmbH