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Reference Materials for Plastic Pollution Measurement Science


Scientific studies on plastic pollution have been conducted for at least 50 years, and over time these research efforts have increased.  Notably, the development of methods for the analysis of microplastic (1 to 1,000 μm) and nanoplastic (1 to 1000 nm) contaminants in the environment has received increased attention, and there is a lack of consistency and standardization among these methods. NIST produces Standard Reference Materials (SRMs) and offers a variety of plastic polymer SRMs with relevance to the study of plastic pollution (see table below).


Microplastic reference materials of different sizes and shapes are required to support environmental studies. Smaller size classes, particularly between 1 µm and 500 µm, are needed to develop microplastic extraction methods, to identify additives in microplastics, and to create in-house spectral libraries for the identification of plastic composition. NIST is working to expand the current reference material inventory to meet this need (see table below). Consumer goods are a major source of mismanaged waste entering the environment, and additional materials under development include plastic consumer products. High density polyethylene (HDPE) milk jugs, polypropylene (PP) disposable cups, and polystyrene (PS) disposable knives were ground in a large batch cryomill in the NIST Reference Material Production Facility to microplastic sizes (< 5 mm). Sieved size classes are being analyzed by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), and pyrolysis-gas chromatography/mass spectrometry (py-GC/MS) before the particles are bottled for distribution.

Picture of a metal bucket containing cryomilled high density polyethylene particles.
Cryomilled plastics will advance standardization of microplastic and nanoplastic methods.
Credit: K. Shaw/NIST


Environmental reference materials with known quantities of microplastics would be useful for validating and standardizing methods to quantify micro- and nanoplastics in the environment. Existing environmental reference materials offered by NIST are typically certified for organic and inorganic chemical pollutants, but until now, the microplastic composition of these materials has not been characterized. Several existing NIST SRMs, such as SRM 1941b Organics in Marine Sediment, SRM 2585 Organic Contaminants in House Dust, SRM 2781 Domestic Sludge, and SRM 2782 Industrial Sludge, will be evaluated for incurred microplastics, and properties of microplastics contained in these SRMs will be characterized.

SRM Title Status 
SRM 1453 Thermal Conductivity - Expanded Polystyrene Board out of stock 
SRM 1473c Low Density Polyethylene Resin  
SRM 1474b Polyethylene Resin  
SRM 1475a Linear Polyethylene (Whole Polymer) out of stock 
SRM 1476a Branched Polyethylene Resin  
SRM 1478 Polystyrene (Narrow Molecular Weight Distribution)  
SRM 1479 Polystyrene (Narrow Molecular Weight Distribution)  
SRM 1482a Linear Polyethylene Narrow Molecular Mass Distribution (13 600 g/mol) out of stock 
SRM 1483a Linear Polyethylene Narrow Molecular Mass Distribution (32 100 g/mol) out of stock 
SRM 1484a Polyethylene, Linear  
SRM 1487 Poly (methyl methacrylate) discontinued 
SRM 1488 Poly(methyl methacrylate) 29 K Narrow Molecular Weight Distribution  
SRM 1690 Polystyrene Spheres (Nominal Diameter 1 µm) out of stock 
SRM 1691 Polystyrene Spheres (Nominal Diameter 0.3 µm) out of stock 
SRM 1961 Nominal 30 micrometer Diameter Polystyrene Spheres  
SRM 1963a Polystyrene Spheres (Nominal Diameter 100 nm) out of stock 
SRM 1964 Polystyrene Spheres (Nominal Diameter 60 nm)  
SRM 1965 Microsphere Slide (10 micrometer Polystyrene Spheres) discontinued 
SRM 2855 Additive Elements in Polyethylene  
SRM 2859 Restricted Elements in Polyvinyl Chloride  
SRM 2860 Phthalates in Polyvinyl Chloride  
SRM 2861 Restricted Elements in Polyvinyl Chloride  
SRM 2870 Relative Permittivity and Loss Tangent 1422 Cross-Linked Polystyrene discontinued 
SRM 2885 Polyethylene (Mass-Average Molar Mass [MW] 6 280 g/mol) out of stock 
SRM 2886 Polyethylene (Mass-Average Molar Mass [MW] 87 000 g/mol) out of stock 
SRM 2887 Polyethylene (Mass-Average Molar Mass [MW] 196 400 g/mol) out of stock 
SRM 705a Polystyrene (Narrow Molecular Weight Distribution)  
SRM 706a Polystyrene (Broad Molecular Mass Distribution)  
SRM 8540 IAEA-CH-7 (Carbon and Hydrogen Isotopes in Polyethylene Foil)  
Created November 29, 2023, Updated May 15, 2024