Detecting Nanoplastic Particles using Correlative Microscopy

Nowadays “microplastics” (MPs) is an already well-known term and micro-sized particles are increasingly found in several consumer products [1]. Moreover, effects of micro- and nanoplastics (NPs) on human health have been investigated and discussed [2]. In this study, the focus is pointed to MPs smaller than 1 µm, with a specific focus on particles in the scale of a couple of 100 nm, which are referred here as NPs. A correlative approach between scanning electron microscopy (SEM, high resolution) and Raman microscopy (chemical identification) was tested to meet the challenges of finding and identifying these small particles. For this purpose standardized polystyrene (PS) beads were mixed into various environments in different concentrations, ranging from ideal (distilled water) to realistic (sea salt, human amniotic fluid), to proof the detection limit of NPs with the so called RISE (Raman Imaging and Scanning Electron microscopy) system [3]. Promising results exhibit detection limits of 2·10-3 µg/L (distilled water), 20 µg/L (sea salt) and 200 µg/L (human amniotic fluid).