Session: Advances in Mass Spectrometry:

Development of analytical methods for the characterization of the low µm-range microplastics (MPs; 1-10 µm) in environment is a quickly emerging scientific field. However, due to the limited sensitivity of the current state of the art monitoring techniques, detection of MPs in different environmental compartments is one of the biggest challenges for their monitoring, source identification and, ultimately, risk assessment.
The present study offers a novel method based on the use of high resolution inductively coupled plasma-mass spectrometry operated in single-event mode (HR-spICP-MS; Nu AttoM ES, Nu Instruments, UK) for the characterization of MPs in water samples and relies on our previous work where for the first time ever sp-ICP-MS based on carbon monitoring was successfully used for the detection and size characterization of polystyrene microspheres with diameters ranging from 2 to 5 μm. This approach relies on the ultra-fast monitoring of the transient 13C⁺ signal by using an Agilent 7900 quadrupole-based ICP-MS instrument (Agilent Technologies, Japan) and single-cell sample introduction system [1].
After this proof of concept study, HR-spICP-MS has been accessed in order to further improve the size detection limit of the developed approach. Efforts were carried out to minimize the C background coming from the dissolved C-species, impurities in the Ar gas and presence of atmospheric CO₂ in the ICP, pointing out the great potential of this technique for the characterization of MPs. Finally, although polymer identification by this technique is not possible, and must rely on other techniques, it is evident that (HR)-spICP-MS is an emerging and complementary technique for the detection and characterization of MPs. Evidently, “thinking-out-of-box” improvements are still needed to optimize the method towards characterization of nanoplastics (1-1000 nm) [2].

Ana Rua-Ibarz

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