![]() ![]() "The new analytical processes permit rapid and precise investigation of concentration, size and composition of micro- and nanoplastics," sums up Dr. A specially developed device, combined with Raman spectroscopy, permits the chemical characterization of different types of nanoplastics. This creates a water flow that captures the particles-depending on their size-and separates them by transporting them at varying speeds. To detect them, we first have to carry out size fractionation and then identify them," explains the researcher.įor this purpose, a field flow fractionation (FFF) system is used. "Nanoparticles like these are difficult or even impossible to discern under a light microscope. Ivleva's team is already working on a modified process. To investigate nanoparticles with diameters of less than 1 µm, however, Dr. Nanoplastics require special detection processes The open-source TUM-Particle Typer 2 software is now available to researchers around the world, and Ivleva's team has published two articles on the process in the journal Analytical and Bioanalytical Chemistry. This allows quick and reliable analysis of the number, size, shape and composition of the microplastics. ![]() In the next step, the laser is directed onto the sample and the scattering is detected and analyzed. The software uses these data to compute the number of particles and fibers and to select the image sections needed for a statistically significant result in the subsequent Raman spectroscopy. The plastic particles are first localized with a light microscope, photographed and measured, and the particles are distinguished from fibers. A single analysis no longer takes weeks, but only a matter of hours.Īlthough the tiny particles still have to be filtered out of the aqueous solution, followed by placement of the filter under the Raman microspectroscope, all remaining steps are carried out by the software developed by the team. "It took us months to investigate a few thousand particles." In the meantime the team has succeeded in automating the detection of microplastics. "When we started, we still had to make manual measurements," recalls the chemist. It took years to develop the tracing process. Because plastics such as polyethylene, polystyrene and polyvinyl chloride scatter the photons in characteristic ways, they each generate signals as unique as a fingerprint.Īutomation instead of manual measurements To analyze plastic particles with a diameter greater than 1 µm (micrometer), they must first be filtered out of the aqueous solution, detected under the microscope and then illuminated with laser light. It works by shining a monochromatic laser source onto a sample and detecting the light scattered by the molecules.Ĭomparing the scattered light against the laser source provides information on the substance under investigation. That means that instead of destroying the particles, we analyze them directly." To do this, the researchers use a method known as Raman microspectroscopy. "Our approach is fundamentally different," says Dr. Plastics can be identified through light scattering With that approach, however, it is not possible to determine the number, size and shape of the plastic particles. Previous methods have relied on the analysis of the residues that are released when the samples are heated. These particles must first be isolated before their concentrations and ultimately their chemical composition are determined. River water, for example, contains massive amounts of suspended solids and fine sand, with plastic accounting for less than 1% of the particles. To be able to detect microplastic particles, the researchers had several hurdles to overcome: The first was the problem of low concentrations. Together with her team, the scientist has developed a new process. Natalia Ivleva at the Chair of Analytical Chemistry and Water Chemistry at TUM. "We urgently need analytical techniques to learn about the size, concentration and composition of these particles," says Dr. The tiny particles, with diameters of less than 5 millimeters, can also absorb and transport contaminants and toxins. Microplastics are everywhere in the environment. ![]()
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