Identification of microplastics and additives from the Lake Erie watershed and the Cuyahoga River via MALDI-MS and DART-MS

Micro(nano)plastics have received increased attention as environmental contaminants due to their harmful effects on ecosystems and human health. Conventional extraction methods for microplastic analysis are often lengthy and complicated, resulting in the loss of important chemical components such as additives. In this study, we provide a complementary approach, utilizing matrix-assisted laser desorption/ionization (MALDI) and direct analysis in real time (DART) mass spectrometry (MS) techniques, with minimal extraction and sample preparation to preserve both polymer and additive information. MALDI-MS was applied to aqueous samples collected along the shores of Lake Erie and the Cuyahoga River, successfully identifying the base polymer(s) in the micro(nano)plastics content of these samples, which included polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene (PE), and polymethylmethacrylate (PMMA). Simultaneously, DART-MS was used to analyze macroplastics debris collected from the same locations, enabling sensitive detection of the additives and plasticizers that are likely leaching into the aquatic environment. DART-MS macroplastics analysis additionally revealed the presence of PE and PEO chains in the plastic litter, corroborating the MALDI-MS data from the water samples and providing strong evidence for contaminant transfer from discarded plastics to the aquatic environment. Finally, DART-MS analysis of the water samples showed additives and plasticizers matching those present in the litter. This study combined both MALDI-MS and DART-MS analysis for the first time, offering a more comprehensive assessment of the base polymer composition and associated additives. By minimizing extraction steps, this approach improves the detection of compounds often lost by conventional methods, ultimately providing deeper insight into microplastic pollution and its toxicological implications. • Micro/nanoplastics (MNPs) and disposed plastics were analyzed by MALDI- and DART-MS • MALDI-MS revealed polymer component(s) and end groups, including ecological changes • DART-MS revealed additives and complementary polymer insight • Common and unique products were detected in different NE Ohio natural water samples • Major polymer degradation pathways to form MNPs involve hydrolysis and oxidation