Institute of Hydrochemistry, Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, Marchioninistr. 17, 81377 Munich, Germany.
Postnova Analytics GmbH, Max-Planck-Str. 14, 86899 Landsberg, Germany.
Anal Chem. 2020 Apr 21;92(8):5813-5820. doi: 10.1021/acs.analchem.9b05336. Epub 2020 Mar 2.
Nanoplastic pollution is an emerging environmental concern, but current analytical approaches are facing limitations in this size range. However, the coupling of nanoparticle separation with chemical characterization bears potential to close this gap. Here, we realize the hyphenation of particle separation/characterization (field-flow fractionation (FFF), UV, and multiangle light scattering) with subsequent chemical identification by online Raman microspectroscopy (RM). The problem of low Raman scattering was overcome by trapping particles with 2D optical tweezers. This setup enabled RM to identify particles of different materials (polymers and inorganic) in the size range from 200 nm to 5 μm, with concentrations in the order of 1 mg/L (10 particles L). The hyphenation was realized for asymmetric flow FFF and centrifugal FFF, which separate particles on the basis of different properties. This technique shows potential for application in nanoplastic analysis, as well as many other fields of nanomaterial characterization.
纳米塑料污染是一个新出现的环境问题，但当前的分析方法在这个尺寸范围内存在局限性。然而，将纳米颗粒分离与化学特性相结合具有缩小这一差距的潜力。在这里，我们实现了颗粒分离/特性（场流分级（FFF）、UV 和多角度光散射）与随后的在线拉曼微光谱（RM）化学鉴定的连接。通过二维光镊捕获颗粒克服了拉曼散射低的问题。该装置使 RM 能够识别尺寸在 200nm 到 5μm 之间、浓度在 1mg/L（10 个颗粒/L）的不同材料（聚合物和无机）的颗粒。该连接实现了不对称流 FFF 和离心 FFF 的连接，这两种方法都是根据不同的性质分离颗粒。该技术在纳米塑料分析以及纳米材料特性的许多其他领域具有应用潜力。
