The outcome of three Erasmus Maris interlaboratory comparisons

The Joint Research Centre produced two well characterised microplastic (MP) Test Materials (TM) and coordinated interlaboratory comparisons (ILC) to support the evaluation of a harmonised analytical method for the determination of MP in water. This report presents the ring trial validation of the Erasmus Maris Standard Operating Procedure (SOP) for counting microplastic particles in water samples. This exercise involving trained teachers assessed recovery and precision using sea water (SW) and river water (RW) samples spiked with TM-062. For ‘SW + TM-062’ and ‘RW + TM-062 + algae’, recoveries of ca. 83 % were obtained, with precisions of ca. 18 %, demonstrating satisfactory performance. An ILC with expert laboratories applying more sophisticated analytical methods showed good agreement with assigned values, confirming that results from the simplified SOP fall within the range of established approaches. The subsequent proficiency testing (PT) round with laboratories of the Technical Group on Marine Litter (TG-ML) demonstrated overall satisfactory performance despite methodological diversity. The findings indicate that the Erasmus Maris SOP is fit for purpose for educational and screening applications. Variability is mainly linked to particle recovery during transfer and filtration and to visual counting. Continued quality assurance through refresher exercises for teachers and participation in PT rounds is recommended.

ROBOUCH Piotr;  EMTEBORG Hakan;  SEGHERS John;  GARCÍA RUIZ Silvia;  ARCOT RAJASHEKAR Anandasagari;  RUIZ-OREJÓN Luis Francisco;  LABIBES Kamel; 

2026-05-29

Publications Office of the European Union

JRC146755

978-92-68-40047-0 (online),   

1831-9424 (online),   

EUR 40737,    OP KJ-01-26-238-EN-N (online),   

https://publications.jrc.ec.europa.eu/repository/handle/JRC146755,   

10.2760/7723626 (online),