Recently, the interest in investigating the contamination of the environment with microplastics (MP, plastic pieces < 5 mm) has increased worldwide. However, reliable procedures for the automatized monitoring of MP are still not available. Here, currently suggested methods are critically evaluated with regard to practical challenges and prospects for standardization. This includes two vibrational spectroscopies, Raman and Fourier transform infrared (FTIR) spectroscopy, and two extraction methods: thermal extraction desorption gas chromatography mass spectrometry (TED-GC-MS) and liquid extraction followed by size exclusion chromatography (SEC).
A soil reference material with known contents of the major MP sources polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET) was employed to compare the methods regarding measurement time, technique handling, detection limits and requirements for sample preparation. It is shown that the respective expectations on the measurements should carefully be considered before selecting an instrumental method and designing a whole analytical protocol including sample preparation. Thus, the selection of appropriate methods depends on whether the contamination extent of a specific environmental site with MP needs to be roughly estimated or if the quantification of the MP content in a given sample is required. In order to obtain overall information on MP in environmental samples, the combination of several complementary approaches should be considered.
Comparison of different methods for MP detection: What can we learn from them, and why asking the right question before measurements matters?
Anna Maria Elert, Roland Becker, Erik Dümichen, Paul Eisentraut, Jana Falkenhagen, Heinz Sturm, Ulrike Braun
Environmental Pollution, Volume 231, Part 2, December 2017, Pages 1256-1264
BAM Department Analytical Chemistry; Reference Materials, Division Structure Analysis and Division Organic Trace and Food Analysis; Department Materials Engineering, Division Mechanics of Polymers; Department Materials Protection and Surface Technology, Division Nanotribology and Nanostructuring of Surfaces