Non-Destructive Extraction and Separation of Nano- and Microplastics from Environmental Samples by Density Gradient Ultracentrifugation

Abstract

Nano-/microplastics (NMPs, particle diameter < 5 mm) are widespread emerging pollutants causing diverse impacts on organisms due to their sizes, shapes, and chemical properties. Despite the fast increase in NMP research, an effective method to separate and identify NMP types from environmental samples is still lacking. Here, we developed a simple and effective approach for the non-destructive extraction and separation of various types of NMPs from environmental samples by density gradient ultracentrifugation (DGU). For the first time, DGU was capable to separate various NMPs from the complex matrix with high selectivity (100%), purity (93%), and applicability. Through a gradually changing density of the density gradient medium by changing the concentrations or volumes of CsCl/water solution (from 0.00065 to 0.01989 g cm–3 mm–1), various NMPs (with particle sizes as little as 50 nm) could be extracted and separated from soil samples with high recovery (78.5–96.0%). We confirmed the effectiveness and compatibility of DGU through a correct identification of all types of NMPs separated from artificial soil samples with Raman spectroscopy, simultaneous thermal analysis (STA), and pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS). DGU is compatible with all analytical processes compared to other existing methods with much less sample pretreatment time (0.5 h). Overall, DGU is an effective and cheap method (2.2 USD/sample) to separate NMPs from environmental samples such as soil and water and, hence, can facilitate research on NMPs related to terrestrial and marine environments as well as human health.

Quantification and Characterization of Fine Plastic Particles as Considerable Components in Atmospheric Fine Particles

“…Among these, three FPPs (PE, PS, and PVC) and two plastic additives [Diisobutyl phthalate (DIBP) and dibutyl phthalate (DBP)] were found in relatively substantial quantities in the samples (details in Supplementary Note 3). This presence was particularly prominent during periods of heightened human activities. , …”

“…This presence was particularly prominent during periods of heightened human activities. 33,34 As depicted in Figure 1a, the average concentration of FPPs was 5.6 μg/m 3 (ranging from 0 to 24.7 μg/m 3 ). Specifically, the average concentrations of PE, PS, and PVC were 4.2 μg/m 3 (with a range of 0−22.7 μg/m 3 ), 0.6 μg/m 3 (ranging from 0 to 1.0 μg/m 3 ), and 0.5 μg/m 3 (ranging from 0 to 1.8 μg/m 3 ), respectively.…”

Water Analysis: Emerging Contaminants and Current Issues

“…A nondestructive extraction and separation technique for MPs and NPs was reported by Jing et al, using density gradient ultracentrifugation (DGU). 249 This method allowed separation of various MPs and NPs from complex matrices with high selectivity and purity. By gradually changing the density of CsCl/water solutions, MPs and NPs could be extracted and separated from soil samples with recoveries of 79−96%.…”

Core–Shell Au@Nanoplastics as a Quantitative Tracer to Investigate the Bioaccumulation of Nanoplastics in Freshwater Ecosystems

“…13,14 Similar, Py-GC-MS has been applied for reliable identification and quantification of micro-and nanoplastics. 15 However, an extra procedure to extract the micro-and nanoplastics from the complex matrix is usually needed when using Py-GC-MS for micro-and nanoplastic detection, 12 despite several efficient extraction methods, e.g., density gradient ultracentrifugation (DGU), 16 pressurized liquid extraction (PLE), 17 having been developed. Besides environmental monitoring, fate and behavior studies of NPs in the laboratory and controlled field could provide reliable and quantitative data for the toxicity, distribution, and bioaccumulation of NPs.…”

“…Though MALDI-TOF MS could provide the mass and molecular information on the detected plastic, a preconcentration step is essential to meet the detection limits of this technique owing to low NP concentration in the environment. , Similar, Py-GC-MS has been applied for reliable identification and quantification of micro- and nanoplastics . However, an extra procedure to extract the micro- and nanoplastics from the complex matrix is usually needed when using Py-GC-MS for micro- and nanoplastic detection, despite several efficient extraction methods, e.g., density gradient ultracentrifugation (DGU), pressurized liquid extraction (PLE), having been developed.…”