Adaptation of a laboratory protocol to quantity microplastics contamination in estuarine waters

One of the most used protocols to extract and quantify MPs is NOAA protocol in aquatic environments. However, there is still no standardized method to extract and quantify MPs in estuarine waters. The aim of this work was to adapt the NOAA protocol to quantify microplastics in estuarine water and provide all the details and changes to improve the efficiency of the method. For that, four types of plastic (PE-LD; PET; PA; PE-HD) were used in artificial samples to test all the steps of the protocol. Several criteria were tested, namely: (i) quantities of H₂O₂ used for organic matter degradation; (ii) temperatures of drying samples; and (iii) density separation efficacy. With the proposed modifications, the microplastics extraction were above 90%, regardless the type of plastic, with PE-LD reaching 100% of efficiency. The new adapted protocol that we propose will allow a better efficiency in extraction and quantification of microplastics in samples from estuarine environments. •Four different types of plastic (PE-LD; PET; PA; PE-HD) were used to test the efficiency of the protocol•Details as the ideal quantity of H₂O₂, temperature and exact quantity of NaCl were tested and defined during the experiments•Efficiency of the microplastics extraction were above 90.