**6. Conclusion**

This chapter has proven that the standard protocol 4484–2 allows for the determination of microplastics in aqueous textile matrices. Indeed, the round robin test was successfully carried out for an interlaboratory comparison test on the standard microfilament suspension. 18 laboratories expressed their interest, and 13 participants had sent their results. The data obtained were the number of microplastics for each sample recognized as microfilaments or particles, and identification of the polymer using vibrational spectroscopy (μ-FTIR and/or μ -Raman) had been performed. Moreover, some microfilament sizes were also indicated. The data collected were statistically elaborated by using the graphical descriptive analysis. The RRT statistical analysis has shown that the proposed protocol can be applied for the identification and counting of microfilaments in water suspension. It can be easily applied in routine analysis in order to verify the correctness of the microplastic identification procedure. Indeed, several laboratories reached a high value of recovery rate (85%), confirming the data obtained by Mossotti et al. [29]. Thus, the proposed protocol can be a suitable tool to evaluate the recovery quality of the single real sample as well as the presence of environmental contaminations.
