Multi-feature round silicon membrane filters enable fractionation and analysis of small micro- and nanoplastics with Raman spectroscopy and nano-FTIR

Meyns, Michaela; Dietz, Frank; Weinhold, Carin; Züge, Heiko; Finckh, Saskia; Gerdts, Gunnar

doi:10.1039/d2ay01036d

Cited by 9 publications

(3 citation statements)

References 52 publications

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“…Efforts are underway to reduce plastic waste, by increasing recycling rates and developing more sustainable alternatives to the traditional plastics, such as bioplastics [13,14]. On the other hand, once the big plastic items break down to small sizes as microplastics (<5 mm) that cannot be directly and easily seen by our naked eyes, the contamination might get much worse [10,15,16]. More seriously, we might have been exposed to this emerging contamination in our daily lives [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

“…Once the laser scans the sample surface by combining Raman spectroscopy with microscopy (as micro-Raman), the scattered signal is collected at specific position and then mapped as a pixel for imaging. The scan thus generates an array of spectra as a hyperspectral matrix that contains hundreds to thousands of spectra, also termed as hyper spectrum [16,28,29]. The image analysis can statistically enhance the sensitivity when compared to the traditional single-spectrum analysis that works as only a pixel in the image.…”

Section: Introductionmentioning

confidence: 99%

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Investigating microplastics and nanoplastics released from food bag ziplock using SEM and Raman imaging

Fang,

Yu,

Gopalan

et al. 2024

Nano Ex.

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Microplastic contamination is a concern in our daily lives, such as being released from self-sealing ziplock (sliderless zipper) plastic bags commonly used for food storage. That is because during the closure and opening process, due to friction and deformation, the male rim inserting into or separating from the female rim can release debris as micro- and nanoplastics (MNP). Herein, we initially observed the released debris using scanning electron microscopy (SEM). Subsequently, Raman imaging was employed to directly visualise the debris scratched on the rim surface and the fallen debris from molecular spectrum perspective. Raman imaging analyses MNP from hundreds to thousands of spectra rather than from a single spectrum or peak, enhancing the signal-to-noise ratio statistically and providing morphological information for quantification. The confocal Raman-based 3D structure mapping of MNP may be susceptible to false images, which can be improved through terrain mapping. Additionally, the weak signal of nanoplastics can be enhanced by reducing scanning pixel size and deconvoluting with surface-fitting algorithm. Consequently, we estimate that approximately 5(±3) MNP per millimetre along the ziplock length may be released during each closure/opening process. Given the use of these plastic bags for food storage, this level of contamination is concerning, warranting careful risk assessment alongside other potential sources of plastic items used in our kitchens. Overall, Raman imaging can be effectively analyse MNP and more broadly nanomaterials, with help of algorithms and SEM.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigating microplastics and nanoplastics released from food bag ziplock using SEM and Raman imaging

Fang,

Yu,

Gopalan

et al. 2024

Nano Ex.

View full text Add to dashboard Cite

show abstract

“…Particles larger than 1 μm are mainly analyzed by conventional techniques such as infrared and Raman spectroscopy. − Both techniques not only provide particle size and composition information but also can be used for industrial online analysis. Particles smaller than 1 μm are usually analyzed by scanning electron microscopy, transmission electron microscopy, dynamic light scattering, etc. , Recently, some infrared- or Raman-based new approaches (nanoFTIR, Raman Tweezers, or optical Raman imaging) also enable NPs analysis. − Although these techniques are effective in detecting the size of NPs, they require complex instrumentation and pure samples, resulting in high detection costs and limited applicable scenarios . Electrochemical technology is a widely used conventional technology in industrial analysis and clinical detection due to its advantages such as simplicity, real-time analysis, and low cost. − By modification or functionalization of electrodes, electrochemical methods can be used to detect substances in various forms such as gas, liquid, and solid.…”

mentioning

confidence: 99%

Convenient Size Analysis of Nanoplastics on a Microelectrode

He,

Xie,

Xiang

et al. 2024

Anal. Chem.

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Chemical recycling is a promising approach to reduce plastic pollution. Timely and accurate size analysis of produced nanoplastics is necessary to monitor the process and assess the quality of chemical recycling. In this work, a sandwich-type microelectrode sensor was developed for the size assessment of nanoplastics. β-Mercaptoethylamine was modified on the microelectrode to enhance its surface positive charge density. Polystyrene (PS) nanoplastics were captured on the sensor through electrostatic interactions. Ferrocene was used as an electrochemical beacon and attached to PS via hydrophobic interactions. The results show a nonlinear dependence of the sensor's current response on the PS particle size. The size resolving ability of the microelectrode is mainly attributed to the small size of the electrode and the resulting attenuation of the electric field strength. For mixed samples with different particle sizes, this method can provide accurate average particle sizes. Through an effective pretreatment process, the method can be applied to PS nanoplastics with different surface properties, ensuring its application in evaluating different chemical recycling methods.

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Sampling of microplastics at a materials recovery facility

Lindstrom,

Conny,

Ortiz-Montalvo

2024

Anal Bioanal Chem

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Detecting, separating, and characterizing airborne microplastics from other airborne particulates is currently challenging due to the various instrumental constraints and related sample preparation hurdles that must be overcome. The ability to measure these real-world environments is needed to better assess the risks associated with microplastics. To that end, the current study focused on developing a methodology for sampling and characterizing airborne microplastics. Particulate sampling was carried out at a municipal materials recovery facility near a conveyer belt containing sorted plastic materials to collect airborne environmental particles on filters. Nucleopore filters were mounted on Teflon support rings, coated with 100 nm aluminum to reduce the background signal for micro-Raman spectroscopy, and marked with a fiducial pattern using a laser engraver. The fiducial pattern was crucial in identifying samples, relocating particles, and efficiently enabling orthogonal measurements on the same samples. Optimum sampling conditions of 2 h at 25 L/min were determined using light microscopy to evaluate the particle loadings. The filters were then cut into slices which were attached to sections of thin beryllium-copper sheeting for easy transfer of the filter between microscopy platforms. Scanning electron microscopy was used to identify carbon-rich particles. Light microscopy was used to identify colored particles which were also carbon-rich which were then analyzed using micro-Raman spectroscopy to identify specific polymers.

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Multi-feature round silicon membrane filters enable fractionation and analysis of small micro- and nanoplastics with Raman spectroscopy and nano-FTIR

Abstract: Visualization of small micro-(20-1 µm) and nanoplastics (< 1 µm) combined with chemical identification is still a challenge. To address this, we designed and manufactured easy-to-handle silicon membrane filters with...

Cited by 9 publications

References 52 publications

Investigating microplastics and nanoplastics released from food bag ziplock using SEM and Raman imaging

Investigating microplastics and nanoplastics released from food bag ziplock using SEM and Raman imaging

Convenient Size Analysis of Nanoplastics on a Microelectrode

Sampling of microplastics at a materials recovery facility

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