Microplastic analysis in environmental samples, FHNW School of Life Sciences

Microplastic pollution from items we use in everyday life has increased by about 50% in the past 20 years, and is a major problem worldwide. Microplastics have been found in the atmosphere, in aquatic and terrestrial environments, and in living organisms including humans. The more they break down in size, the harder they are to measure.

A promising approach for detecting and quantifying microplastics in environmental samples is pyrolysis gas chromatography coupled to mass spectrometry (Py-GC/MS).

However, reliable protocols are not yet available, and accurate quantification is challenging, espeically when more than one polymer (microplastic) is present in a sample.

In this project, our team aimed to gather initial data toward establishing international standards for microplastic assessment using Py-GC/MS.

The project focused on:

• developing a database of single, double, and triple polymer mixtures
• testing different diluters for the accurate preparation of calibration standards for quantification purposes
• understanding if gas phase reactions occur during pyrolysis when two or more microplastics are present in a sample

We chose seven different polymers due to their prevalence in daily plastic items and appliances:

• polyethylene terephthalate (PET), used for drinking and other containers
• polyvinyl chloride (PVC) used for pipes, cables, flooring, and siding
• methylene diphenyl diisocyanate polyurethane (MDI-PU), used for insulations, coatings, and molded goods
• polyethylene (PE), used for wrapping, films, and containers
• polypropylene (PP), used in automotive, medical and food packaging
• polyamid 6 also called nylon 6 (PA-6), used in clothing, automotive and industrial parts
• polyamide 66 (PA-66), used in automotive and mechanical applications