Nanotechnology Session:

Friday, September, 30th, 2022: 01:00 pm

Chairs: Ulrike Taylor and Wolfgang Fritzsche

Claudia Lorenz

Microplastics – Small particles, big challenges

Aalborg University, Department of the Built Environment, Denmark

With global plastic production inexorable on the rise, the occurrence of plastic pollution in the environment has been acknowledged as an emerging topic of international concern. This plastic litter is derived mainly from the inadequate disposal and management of plastic waste and will, due to physical and chemical weathering, get brittle and release a multitude of smaller and smaller plastic particles termed microplastics (1 μm – 5 mm) and nanoplastics (<1 μm).
In recent years, this microplastic pollution has received increasing attention not only from the scientific community but also from society and policymakers. However, its extent and the resulting impacts on the aquatic environment and human health remain largely unknown. This is especially true regarding the conclusive identification and characterization of “small” microplastics. The smaller the particles, the bigger the challenges related to extracting and identifying microplastics in complex environmental matrices. Furthermore, various methods for sampling, extraction, and analysis of microplastics are available, which complicate the establishment of standardized operational protocols (SOPs). So far, no single analytical method exists that can provide reliable identification and quantification of all microplastic polymers and simultaneously assess desired characteristics, e.g., size, shape, and mass.
Light and, more recently, fluorescence microscopy are widely used in microplastic research to visualize and characterize microplastics. Microscopy can be combined with spectroscopic techniques, like Fourier Transform Infrared (FT-IR) and Raman spectrometry to assess also the chemical composition. Thermoanalytical methods and mass spectrometry further provide relevant information regarding the polymers’ mass and composition, including additives.
Historically, flow cytometry was used to enumerate and characterize cells but has long since broadened in scope and is now applied for all microparticles, including microplastics. Although only a few studies have explored the possibility of utilizing flow cytometry for the quantification and characterization of microplastics in environmental samples, flow cytometry has become a helpful tool in the field of microplastic research for, e.g., the validation and quality assurance of digestion protocols, aiding in recovery experiments, and setup of ecotoxicological experiments.
Some of these applications will be presented here with a focus on the use of the FlowCam® (Yogogawa Fluid Imaging Technologies), an imaging particle analyzer combining the benefits of flow cytometry, microscopy, and digital imaging. This instrument is used worldwide for quality control for (bio)pharmaceutical products, water quality monitoring, counting cells of cyanobacteria and other marine and freshwater plankton organisms, and microplastics research.

Claudia Lorenz is a PostDoc at Aalborg University in the Department of the Built Environment. She is a Marine Biologist and has been working in the interdisciplinary field of microplastic research since 2014. During her PhD she was working at the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research on Helgoland investigating the spatial distribution of microplastics in the North Sea. She received a PhD scholarship from the Deutsche Bundesstiftung Umwelt (DBU) and got her PhD in Biology from Jacobs University Bremen.
Her research focus has been on optimization of sample preparation and analysis of microplastics in various environmental matrices where imaging of fluids also plays a role. Further research interests include processes driving the transport, fate, and biological interactions of microplastics as well as other aquatic pollutants.

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