Rapid fingerprinting of source and environmental microplastics using direct analysis in real time-high resolution mass spectrometry

• Published in: Analytica chimica acta Vol. 1100; pp. 107 - 117
• Main Authors: Zhang, Xianming, Mell, Alicia, Li, Frederick, Thaysen, Clara, Musselman, Brian, Tice, Joseph, Vukovic, Dragan, Rochman, Chelsea, Helm, Paul A., Jobst, Karl J.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.03.2020
• Subjects: Chemical fingerprinting; Direct Analysis in Real Time; Environmental mass spectrometry; High-resolution mass spectrometry; Microplastics; Environmental mass spectrometry; Microplastics; High-resolution mass spectrometry; Direct Analysis in Real Time; Chemical fingerprinting
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2019.12.005

Microplastics are ubiquitous in the aquatic and terrestrial environment. To prevent further contamination, methods to determine their sources are needed. Techniques to quantify and characterize microplastics in the environment are still evolving for polymers and the additives and leachable substances embedded therein, which constitute the “chemical fingerprint” of an environmental microplastic. There is a critical need for analytical methods that yield such diagnostic information on environmental microplastics that enables identification of their composition and sources of pollution. This study reports on a novel approach for rapid fingerprinting of environmental microplastics and the screening of additives using Direct Analysis in Real Time (DART)-high resolution mass spectrometry. A variety of plastic samples were investigated, including virgin pre-production pellets, microbeads from personal care products, microplastics found in the aquatic environment, and synthetic fibers. The resulting mass spectra display ∼10,000 discrete peaks, corresponding to plastic additives released by thermal desorption and polymer degradation products generated by pyrolysis. These were used to characterize differences among plastic types, microplastic source materials, and environmental samples. Multivariate statistics and elemental composition analysis approaches were applied to analyze fingerprints from the mass spectra. This promising analytical approach is sensitive, (potentially) high-throughput, and can aid in the elucidation of possible sources of microplastics and perhaps eventually to the analysis of bulk environmental samples for plastics. [Display omitted] •Microplastics are characterized by Direct Analysis in Real Time-high resolution mass spectrometry.•Thermal decomposition thereof yields a mixture of products, i. e its “chemical fingerprint”.•Chemical fingerprints are compared using multivariate statistics and graphical visualization.•The approach may be used to determine the identity of microplastics and potentially their sources.•The method is applied to microplastics from Lake Ontario as well as various personal care products.