Plastic waste is considered one of the most significant ecological challenges for modern society. In particular, the fraction of plastic particles smaller than 5 mm, known as microplastics, poses a serious risk for the environment and human health.1 Although the large-scale use of industrial polymers only began in the middle of the last century, recent expeditions have demonstrated a global penetration of microplastics into ecosystems, including the most remote regions, such as the Arctic and the deep sea, far away from any industrial activity.1–3 As a result, microplastics were identified as a group of highly mobile and persistent environmental pollutants.

In this work, inductively coupled plasma-time-of-flight-mass spectrometry (ICP-TOFMS) as well as quadrupole ICP-MS are used to detect and analyse single microplastic particles. Both the major element carbon from the base polymer as well as metal impurities including europium are studied quasi-simultaneously thanks to TOFMS detection. Based on these spectral TOFMS data, a new approach to define and calculate a method detection limit is discussed. It used advanced algorithms to incorporate multi-element capabilities of ICP-TOFMS to move beyond state of the art critical limits.

While the novel view on detection limits focuses on the smallest plastic particles that can be detected, environmentally relevant microplastic particles cover a broad range of sizes that reaches several tens of micrometres. Suspensions of these particles often exhibit low stability and particle concentrations may vary severely. In order to improve the accuracy of the presented ICP-TOFMS method, we used flow cytometry to obtain accurate particle number concentrations to investigate the transport efficiency of larger microplastic particles.

References
[1] M. Bergmann, S. Mützel, S. Primpke, M. B. Tekman, J. Trachsel and G. Gerdts, Sci. Adv., 2019, 5, 1–10.
[2] S. M. Abel, S. Primpke, I. Int-Veen, A. Brandt and G. Gerdts, Environ. Pollut., 2021, 269, 116095.
[3] S. Allen, D. Allen, V. R. Phoenix, D. Galop, G. Le Roux, P. Durántez Jiménez, A. Simonneau, S. Binet and D. Galop, Nat. Geosci., 2019, 12, 339–344.