Towards Raman Automation for Microplastics: Developing Strategies for Particle Adhesion and Filter Subsampling

Automation and subsampling have been proposed as solutions to reduce the time required to quantify and characterize microplastics in samples using spectroscopy. However, there are methodological dilemmas associated with automation that are preventing its widespread implementation including ensuring particles stay adhered to the filter during filter mapping and developing an appropriate subsampling strategy to reduce the time needed for analysis. We provide a solution to the particle adherence issue by applying Skin Tac, a non-polymeric permeable adhesive that allows microplastic particles to adhere to the filter without having their Raman signal masked by the adhesive. We also explore different subsampling strategies to help inform how to take a representative subsample. Based on the particle distributions observed on filters, we determined that assuming a homogenous particle distribution is inappropriate and can lead to over- and under-estimations of extrapolated particle counts. Instead, we provide recommendations for future studies that wish to subsample to increase the throughput of samples for spectroscopic analysis.

[1]  George Sarau,et al.  Small-sized microplastics and pigmented particles in bottled mineral water. , 2018, Water research.

[2]  Livia Cabernard,et al.  Comparison of Raman and Fourier Transform Infrared Spectroscopy for the Quantification of Microplastics in the Aquatic Environment. , 2018, Environmental science & technology.

[3]  J. Marques,et al.  Occurrence of microplastics in commercial fish from a natural estuarine environment. , 2018, Marine pollution bulletin.

[4]  Jes Vollertsen,et al.  Microplastics in urban and highway stormwater retention ponds , 2019, Science of The Total Environment.

[5]  M. Diamond,et al.  Capturing microfibers - marketed technologies reduce microfiber emissions from washing machines. , 2019, Marine pollution bulletin.

[6]  Stephanie B. Borrelle,et al.  Rethinking microplastics as a diverse contaminant suite , 2019, Environmental toxicology and chemistry.

[7]  Boyan Slat,et al.  River plastic emissions to the world's oceans , 2017, Nature Communications.

[8]  B. Richards,et al.  Synthetic fibers as an indicator of land application of sludge. , 2005, Environmental pollution.

[9]  C. Zarfl,et al.  Promising techniques and open challenges for microplastic identification and quantification in environmental matrices , 2019, Analytical and Bioanalytical Chemistry.

[10]  Gunnar Gerdts,et al.  Spatial distribution of microplastics in sediments and surface waters of the southern North Sea. , 2019, Environmental pollution.

[11]  P. Ross,et al.  A novel, density-independent and FTIR-compatible approach for the rapid extraction of microplastics from aquatic sediments , 2017 .

[12]  Hans-Ulrich Humpf,et al.  Analysis of microplastics in water by micro-Raman spectroscopy: Release of plastic particles from different packaging into mineral water. , 2018, Water research.

[13]  P. Ross,et al.  Retention of microplastics in a major secondary wastewater treatment plant in Vancouver, Canada. , 2018, Marine pollution bulletin.

[14]  R. E.,et al.  A semi-automated Raman micro-spectroscopy method for morphological and chemical characterizations of microplastic litter. , 2016, Marine pollution bulletin.

[15]  G. Sarau,et al.  Development of an optimal filter substrate for the identification of small microplastic particles in food by micro-Raman spectroscopy , 2017, Analytical and Bioanalytical Chemistry.

[16]  M. Healy,et al.  Microplastics in Sewage Sludge: Effects of Treatment. , 2017, Environmental science & technology.

[17]  Torkel Gissel Nielsen,et al.  A critical assessment of visual identification of marine microplastic using Raman spectroscopy for analysis improvement. , 2015, Marine pollution bulletin.

[18]  R. Niessner,et al.  Raman microspectroscopy as a tool for microplastic particle analysis , 2018, TrAC Trends in Analytical Chemistry.

[19]  M. Mallory,et al.  Plastics and other anthropogenic debris in freshwater birds from Canada. , 2016, The Science of the total environment.

[20]  Jae Bem You,et al.  Fluorescent Dyes for Visualizing Microplastic Particles and Fibers in Laboratory-Based Studies , 2019, Environmental Science & Technology Letters.

[21]  R. Akhbarizadeh,et al.  Microplastic pollution in deposited urban dust, Tehran metropolis, Iran , 2017, Environmental Science and Pollution Research.

[22]  Nikolai Maximenko,et al.  A global inventory of small floating plastic debris , 2015 .

[23]  C. Laforsch,et al.  Pigments and plastic in limnetic ecosystems: A qualitative and quantitative study on microparticles of different size classes. , 2016, Water research.

[24]  Paulo J A Ribeiro-Claro,et al.  Identification of microplastics using Raman spectroscopy: Latest developments and future prospects. , 2018, Water research.

[25]  G. Gerdts,et al.  Automated identification and quantification of microfibres and microplastics , 2019, Analytical Methods.

[26]  T. Mincer,et al.  An approach for extraction, characterization and quantitation of microplastic in natural marine snow using Raman microscopy , 2017 .

[27]  P. Helm,et al.  Sources and sinks of microplastics in Canadian Lake Ontario nearshore, tributary and beach sediments. , 2016, Marine pollution bulletin.

[28]  Melanie Bergmann,et al.  High Quantities of Microplastic in Arctic Deep-Sea Sediments from the HAUSGARTEN Observatory. , 2017, Environmental science & technology.

[29]  Gunnar Gerdts,et al.  An automated approach for microplastics analysis using focal plane array (FPA) FTIR microscopy and image analysis , 2017 .

[30]  C. Rochman,et al.  Increasing the accessibility for characterizing microplastics: Introducing new application-based and spectral libraries of plastic particles (SLoPP & SLoPP-E). , 2020, Analytical chemistry.

[31]  Rasmus Lund Jensen,et al.  Simulating human exposure to indoor airborne microplastics using a Breathing Thermal Manikin , 2019, Scientific Reports.

[32]  Stephan Saalfeld,et al.  Globally optimal stitching of tiled 3D microscopic image acquisitions , 2009, Bioinform..

[33]  S. Godtfredsen,et al.  Ullmann ' s Encyclopedia of Industrial Chemistry , 2017 .

[34]  Richard C. Thompson,et al.  Development and optimization of a standard method for extraction of microplastics in mussels by enzyme digestion of soft tissues , 2017, Environmental toxicology and chemistry.

[35]  Won Joon Shim,et al.  Identification methods in microplastic analysis: a review , 2017 .

[36]  E. Lahive,et al.  Microplastics in freshwater and terrestrial environments: Evaluating the current understanding to identify the knowledge gaps and future research priorities. , 2017, The Science of the total environment.

[37]  Richard C. Thompson,et al.  The Deposition and Accumulation of Microplastics in Marine Sediments and Bottom Water from the Irish Continental Shelf , 2017, Scientific Reports.

[38]  Zhong-Min Wang,et al.  Novel method for the extraction and identification of microplastics in ocean trawl and fish gut matrices , 2017 .