FT-IR analysis for monitoring marine microplastics

Persistent plastics are hardly degraded and accumulate in the marine environment. Together with primary microplastics the fragmentation of larger plastic litter leads to an increasing amount of small plastic particles, so-called microplastics in the oceans. Due to their size (< 5 mm), these have the potential of entering marine food webs. For a reliable evaluation and an assessment of food web effects, a detailed quantitative and qualitative monitoring of microplastics in the marine environment is highly required. Fourier Transform infrared (FT-IR) spectroscopy offers the possibility of the urgendly needed proper identification of microplastic particles in environmental samples. However, standard FT-IR spectroscopy still requires time- and labour-consuming pre-sorting of particles by hand. Hence, small or less abundant microplastics are potentially overlooked. A highly promising FT-IR extension - FT-IR Imaging - allows for detailed and unbiased high throughput analysis of especially the small fraction of microplastics in a given sample without prior pre-sorting by hand. We show first result of the project MICROPLAST which has the aims of (1) the development/optimisation of appropriate methods for the extraction of microplastic particles from complex matrices (e.g. sediment, plankton, tissue), (2) the evaluation of FT-IR imaging for the analysis of microplastics and the development of procedures for its routine application, (3) the generation of data on the pollution of the pelagic and benthic zone with microplastic particles of verified polymer origin in German coastal waters.