Separation and Identification of Nanoplastics via a Two-Phase System Combined with Surface-Enhanced Raman Spectroscopy

Abstract

Nanoplastics, novel environmental pollutants widely dispersed, present challenges due to limited, dependable detection methods, particularly for trace levels. This study introduces a novel approach that integrates liquid-phase self-assembly nanoparticle technology with surface-enhanced Raman spectroscopy (SERS) for the precise detection of nanoplastics. Utilizing hydrophobic−lipophilic interactions and SERS technology, we developed silver nanoparticles (Ag NPs)@poly(methyl methacrylate) (PMMA) films (Ag NPs@ PMMA films) for the efficient extraction and simultaneous detection of polystyrene (PS) and polyethylene terephthalate (PET) nanoplastics at extremely low concentrations (e.g., 10 −11 mg/mL for 20 nm PS nanoplastics and 10 −8 mg/mL for 70 nm PET nanoplastics). It also demonstrates a linear correlation between SERS intensity (y) and the logarithm of nanoplastics' concentration (lg c) at extremely low levels. This technique's applicability extends to real environmental samples, such as seawater, oysters, and bottled water, enabling both qualitative and quantitative detection of PS and PET nanoplastics. For example, it successfully identifies 1.23 × 10 −10 mg/mL PS nanoplastics in seawater samples and 8.61 × 10 −5 mg/ mL PET nanoplastics in bottled-water samples. Overall, these findings provide a reliable basis for trace nanoplastic detection in the environment, addressing a pressing environmental concern.

Assessing Microplastics and Nanoparticles in the Surface Seawater of Venice Lagoon—Part I: Methodology of Research

“…Multiple analytical techniques based on mass or particle size determinations are usually required to obtain information about the concentration, chemical composition, and shape of MPs and NPs. MP identification techniques include microscopic observations [36], µ-Raman [37,38], Fourier transform infrared spectroscopy (FTIR) [38,39], µ-FTIR [31], scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDX) [36,38], and micro-optofluidic platform [36,40], while the NPs have been evaluated using thermal desorption-proton transfer reaction-mass spectrometry (TD-PTR-MS) [29,41], dynamic light scattering (DLS) [26,42,43], transmission electron microscopy (TEM) [44,45], surface-enhanced Raman spectroscopy (SERS) [46], and pyrolysis-gas chromatography/mass spectrometry Py-GC/MS analytical techniques [47]. Since no single analytical method is able to obtain the physical (size, shape, and color) and chemical (polymer type) characteristics of MPs in a single step, the combination of several parallel approaches should be applied and considered.…”

A Scalable Synthesis of Ag Nanoporous Film As an Efficient SERS-Substrates for Sensitive Detection of Nanoplastics

“…Thus, the accurate detection of nanoplastics is essential for various fields such as food safety and environmental monitoring . Recently, research efforts have been directed toward developing analytical methods to detect smaller nanoplastic contamination in the environment. − However, sensitive detection of nanoplastics with low concentration levels in complex environmental samples remains elusive due to the smaller size fraction of particulate nanoplastics . Surface-enhanced Raman scattering (SERS) spectroscopy has emerged as a powerful, nondestructive spectroscopy technique that offers sensitive identification of analytes with high sensitivity and the ability to identify molecular fingerprints. − To achieve high sensitivity and good signal reproducibility as well as stability of the SERS substrates, various strategies have been developed. − In particular, “hotspot” engineering in the gaps of plasmonic NPs such as Ag, Au, and Cu, − designing three-dimensional (3D) plasmonic nanostructures, , plasmonic NPs on 2D materials such as graphene, MoS 2 , Mxane, and their heterostructures have been widely studied. − Nevertheless, the fabrication of a SERS substrate with maximum “hotspots” density for a highly reproducible signal and implementation of the plasmonic NP substrates in direct detection of target analytes in complex environments is still elusive …”