Scanning electron microscopy micrograph of a microplastic particle (origin: garbage bag)
Source: BAM
Microplastic particles are considered harmful to health in the public awareness and receive a high media attention. Science therefore has the task of studying the small particles, which are mainly produced by natural weathering and subsequent fragmentation of improperly disposed plastic products (e.g., beverage containers, plastic cups, garbage bags), in all their forms (round, angular, fibers) and sizes (1-1000 µm) to prevent long-term damage to flora and fauna. It is important to understand their occurrence in nature in order to eliminate possible entry paths.
Plastics usually consist of a high percentage of polymers (long-chain hydrocarbons) and only small amounts of additives, such as color pigments or UV stabilizers. These polymers can be clearly analysed in terms of their identity, size, and shape using imaging and microscopic techniques combined with spectroscopy. Another option is thermoanalytical methods, in which a sample is heated to such an extent that the particles decompose. The type of plastic and its mass can be clearly determined from the decomposition products. Both groups of methods have become well established in recent years, with the result that the first international standards (ISO 16094-2 and ISO/FDIS 16094-3) for detection have recently been published. However, accurately measuring the number or mass of particles is challenging because the small solid particles, which vary greatly in size and shape, are distributed very unevenly in water, soil, or air samples, and there are also many natural particles of the same size. The microplastic particles must therefore be carefully separated from the natural particles without changing their number or size. All this leads to large differences in particle number and mass from laboratory to laboratory. BAM is developing microplastic reference material with known particle numbers and masses to enable comparative measurements and thus evaluate and optimize sample preparation and measurement procedures.
As part of the publication presented here, BAM conducted an international comparison test with 85 participants from all around the world. The work was funded by a Horizon Europe project (965367) under the umbrella of VAMAS (TWA45).
Interlaboratory Comparison Reveals State of the Art in Microplastic Detection and Quantification Methods
Dmitri Ciornii, Vasile-Dan Hodoroaba, Volker Wachtendorf, Petra Fengler, Korinna Altmann
Analytical Chemistry, 2025