Group of Applied Analytical Chemistry (QANAP) and Instituto Universitario de Medio Ambiente (IUMA), University of A Coruña, E-15071 A Coruña, Spain.
Group of Applied Analytical Chemistry (QANAP) and Instituto Universitario de Medio Ambiente (IUMA), University of A Coruña, E-15071 A Coruña, Spain.
Spectrochim Acta A Mol Biomol Spectrosc. 2021 Dec 15;263:120162. doi: 10.1016/j.saa.2021.120162. Epub 2021 Jul 10.
The EU goal to reduce marine plastic litter by ca. 30% by 2020 stressed the need to deploy analytical methods to ascertain the polymeric nature of a residue. Furthermore, as plastics age under natural conditions and usual databases do not include their weathered spectra, (micro)plastics in environmental samples may be unidentified. In this paper, polyamide (nylon) microplastics weathering was monitored because of its ubiquity in household commodities, clothes, fishery items and industry, whose residues end up frequently in the environment. Infrared spectra (ATR and microreflectance) and Scanning Electron Microscopy (SEM) images were collected periodically while exposing nylon to controlled weathering. It was seen that ATR was more sensitive than microreflectance to monitor the structural evolution of polyamide and that the spectra and the surface of weathered microplastics showed remarkable differences with the pristine material, which stresses the need for considering its evolution when identifying microplastics in environmental studies. The evolution of six band ratios related to the chemical evolution of this polymer are presented. SEM images revealed the formation of secondary microplastics at the most advanced weathering stages of polyamide.
欧盟目标是到 2020 年减少约 30%的海洋塑料垃圾，这强调了需要部署分析方法来确定残留物的聚合性质。此外，由于塑料在自然条件下老化，并且通常的数据库不包括其风化的光谱，因此环境样品中的（微）塑料可能无法识别。在本文中，监测了聚酰胺（尼龙）微塑料的风化情况，因为它在家庭用品、衣服、渔业用品和工业中无处不在，其残留物经常最终进入环境。在将尼龙暴露于受控风化条件下时，定期收集红外光谱（ATR 和微反射率）和扫描电子显微镜（SEM）图像。结果表明，ATR 比微反射率更敏感，可监测聚酰胺的结构演变，风化微塑料的光谱和表面与原始材料有明显差异，这强调了在环境研究中识别微塑料时需要考虑其演变。本文还提出了与这种聚合物化学演变相关的六个波段比的演变。SEM 图像揭示了在聚酰胺最先进的风化阶段形成了二级微塑料。
