Spectro‐Microscopic Techniques for Studying Nanoplastics in the Environment and in Organisms

Abstract

Nanoplastics (NPs), small (< 1 μm) polymer particles formed from bulk plastics, are a potential threat to human health and the environment. Orders of magnitude smaller than microplastics (MPs), they might behave differently due to their larger surface area and small size, which allows them to diffuse through organic barriers. However, detecting NPs in the environment and organic matrices has proven to be difficult, as their chemical nature is similar to these matrices. Furthermore, as their size is smaller than the (spatial) detection limit of common analytical tools, they are hard to find and quantify. We highlight different micro-spectroscopic techniques utilized for NP detection and argue that an analysis procedure should involve both particle imaging and correlative or direct chemical characterization of the same particles or samples. Finally, we highlight methods that can do both simultaneously, but with the downside that large particle numbers and statistics cannot be obtained.

The Toxicity of Plastics

“…Visual methods by microscopy [scanning electron (SEM), transmission electron (TEM), with the possibility of a specific configuration for nanosizes, fluorescence microscopy with stimulated emission depletion (STED)], spectrometry methods [Raman, Fourier transform infrared spectroscopy-attenuated total reflection (FTIR ATR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy-infrared spectroscopy (AFM-IR, nanoIR energy-dispersive X-ray spectroscopy)] and thermal analysis by pyrolysis gas chromatography/mass spectrometry (Pyr-GC/MS) complete the identification and the quantification, including the chemical/elemental analysis [63][64][65][66][67]. The characterization of nanoplastics was unavailable until very recently [68], but has been actively researched with encouraging results, in spite of relevant challenges and limitations, such as low or no crystallinity and the ubiquitous distribution of the incorporated elements (C, H, N, O) [69,70].…”