Are there reliable sources of spiked particles that are well characterized for size, shape and plastic chemistry?

Answer Explanations

• Yes (please explain and provide sources)

  Expert 3
  There are many suppliers for these materials (LabMix, MicroplasticSolutions, Spex), but I don't think these are valid in terms of chemistry studies, as these are often materials with surface modifications and/or sold in the presence of surfactants, which may alter their behavior. 
• Yes (please explain and provide sources)

  Expert 9
  We have used for determination of MPs in air, drinking water, and atmospheric deposition, PE MPs particles available from Cospheric™, California, USA.
• Yes (please explain and provide sources)

  Expert 2
  Yes, there are reported reliable sources of well-characterized spiked microplastic and nanoplastic particles in particularly for use in research, environmental analysis, and toxicology studies. These reference materials are defined by known properties such as size, shape, and polymer chemistry. There are well known commercial suppliers such as Polysciences, Inc. that offer polystyrene and PMMA particles in sizes ranging from nanometers to tens of microns, often having spherical shape and available in fluorescent or non-fluorescent forms. Additionally, Cospheric LLC offers monodisperse microspheres of various polymers (e.g., PE, PS, PMMA) having different options for density-specific particles and fluorescent labeling. Other companies such as Microparticles GmbH, supplies a wide range of polymer types with functionalizationed surfaces  and fluorescent tags. Also, the well know material supplier, Sigma-Aldrich/Merck  offers polystyrene microspheres, commonly used for calibration and particle tracking. In addition to the commercial suppliers, there are numerous research collaborations and reference material initiatives that play a crucial role in the advancement of the availability of standardized microplastic particles. The National Institute of Standards and Technology (NIST) has developed standard reference materials (SRMs) for particle size analysis and is actively working to extend these efforts to also include plastic particles. The Versailles Project on Advanced Materials and Standards (VAMAS) is engaged in international efforts to harmonize protocols for microplastic characterization. Similarly, the European Commission’s Joint Research Centre (JRC) is leading the development of harmonized testing methods and reference materials specifically for micro- and nanoplastics. Moreover, there are numerous academic consortia that administrates large-scale projects, like the initiatives PlasticsFatE, MICRO-FATE, and EUROqCHARM, that currently generate and report standardized microplastic particles and publish protocols for their use. 
• No

  Expert 4
  Several efforts are underway for providing such sources. The Joint Research Centre of the EU in Ispra (Italy) has almost finished a set of particles but these are not yet generally available. 
• No

  Expert 6
  There are no reliable sources of material with all size, shape and plastic chemistry. However, there are sources of particles with certain characteristics. Frontier lab offers microplastics with plastic chemistry information and concentration. HPU offers polymer standards with plastic chemistry information. Cospheric offers (Microspheres, Nanospheres, Precision Spherical Particles - Cospheric Ships Globally - US-based Manufacturer) MNPs with well defined size. In terms of shape, Cospheric offers all spheres for materials. Whether perfect sphere is good representation for MNP studies is to be debated. 
• Yes (please explain and provide sources)

  Expert 8
  NIST SRMs of various polymers and with very specific size ranges. They are very limited on polymer types and sizes.
  HPU Polymer Kit 1.0 as mentioned in the paper has a nice diversity of polymers, as does Scipoly's Polymer Sample Kit, but these are typically too large for microplastic spikes.
• Yes (please explain and provide sources)

  Expert 7
  
  Recommended Suppliers of Spiked MNP Standards
  
  

  1. Cospheric LLC (cospheric.com)
     
     
     • Specializes in microspheres and nanospheres made from polymers like polyethylene, polystyrene, PMMA, and more.
     • Offers particles with tight size distributions, custom densities, and fluorescent or colored options.
     • Widely used in environmental and biomedical research for method development and calibration 
       .
  2. SINTEF (Norway)
     
     
     • Provides custom microplastic and nanoplastic test materials for research.
     • Offers advanced characterization using µFTIR, µRaman, and pyrolysis-GC/MS.
     • Focuses on quality assurance and inter-laboratory harmonization 
       .
  3. Polysciences, Inc.
     
     
     • Supplies monodisperse polystyrene and PMMA beads in a wide range of sizes.
     • Often used in toxicology and uptake studies.
  4. Sigma-Aldrich / MilliporeSigma
     
     
     • Offers standardized polymer particles for analytical method development.
     • Includes options for surface-modified or fluorescent-tagged particles.
• No

  Expert 1
  For a few plastic types, well characterized particles are commercially available.  For example, nano size particles made of polystyrene (PS) and polymethyl methacrylate (PMMA) are available (Non-functionalized Polystyrene - Bangs Laboratories, Inc.). Micro size particles of PE and PVC are commercially available (e.g., Cospheric LLC, Santa Barbara, CA, USA; Polyethylene Nanospheres 200nm-9900nm (1-10um) for environmental studies of microplastic pollutants). However, currently,  nano-size particle standards of those polymers except PS and PMMA are not available. Even when such nanoparticles are produced, the purities low in the range of 50-70%.  This article can make a recommendation about analytical standards for MNPs.  Commercial vendors should make micro and nano sized MNPs of various types for help with harmonizing quantification.