Wang Tong, Li Shu, Mu Run, Lu Zhengwei, Su Jie, Chen Jing, Zhan Jinhua
Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China.
Anal Chem. 2024 Dec 10;96(49):19545-19552. doi: 10.1021/acs.analchem.4c04284. Epub 2024 Nov 21.
Microplastics and nanoplastics are emerging contaminants that pose a threat to the environment and human. Spectroscopic technologies are advantageous in analyzing nanoplastics, but it is challenging to selectively detect nanoplastics with different size thresholds. In this work, the hyphenated method of electrosorption and surface-enhanced Raman spectroscopy (ES-SERS) was developed for the simple, rapid, and size-resolved analysis of trace polystyrene (PS) nanoplastics from 20 to 300 nm. A rough silver was used as both the working electrode for electrosorption and the substrate for the SERS response. By applying a positive electric potential to the rough silver, the PS nanoplastics accelerated toward the silver surface and were adsorbed tightly at the SERS "hot spot" inside the rough silver nanostructure. The proposed ES-SERS method achieved a detection limit of 100 ng/L for 300 and 100 nm PS, 50 ng/L for 50 nm PS, and 30 ng/L for 20 nm PS nanoplastics. It is worth noting that smaller nanoplastics typically exhibit larger analytical enhancement factor values in ES-SERS. According to the difference in electromigration behavior of PS in various sizes, PS nanoplastics under a certain size can be selectively enriched and detected by controlling the electrosorption time. The ES-SERS method was successfully demonstrated for detecting nanoplastics released from the lids of disposable beverage cups. This work opens up new possibilities for size-resolved analysis of nanoplastics.
微塑料和纳米塑料是新出现的污染物，对环境和人类构成威胁。光谱技术在分析纳米塑料方面具有优势，但选择性检测不同尺寸阈值的纳米塑料具有挑战性。在这项工作中，开发了电吸附与表面增强拉曼光谱联用方法（ES-SERS），用于对20至300纳米的痕量聚苯乙烯（PS）纳米塑料进行简单、快速且尺寸分辨的分析。粗糙银既用作电吸附的工作电极，又用作SERS响应的基底。通过对粗糙银施加正电势，PS纳米塑料加速向银表面移动，并紧密吸附在粗糙银纳米结构内部的SERS“热点”处。所提出的ES-SERS方法对300纳米和100纳米的PS检测限为100纳克/升，对50纳米的PS为50纳克/升，对20纳米的PS纳米塑料为30纳克/升。值得注意的是，较小的纳米塑料在ES-SERS中通常表现出更大的分析增强因子值。根据不同尺寸PS的电迁移行为差异，通过控制电吸附时间可以选择性地富集和检测一定尺寸以下的PS纳米塑料。ES-SERS方法已成功用于检测一次性饮料杯盖子释放的纳米塑料。这项工作为纳米塑料的尺寸分辨分析开辟了新的可能性。
