Contamination issues as a challenge in quality control and quality assurance in microplastics analytics.

Microplastics are widely distributed environmental contaminants. To understand their impacts on the environment and health, more high-quality results are needed. Since microplastics are present in every environment, including indoor air, proper precautions must be adopted in order to prevent contamination of samples and overestimation of environmental concentrations. Thus, to guarantee a proper quality of results, researchers must adopt strict contamination control measures. This review was conducted to understand current contamination control practices. A total of 50 studies published in 2019 were reviewed, including sampling of biota, air, soil, sediment, freshwater and saltwater, regarding 10 contamination control parameters. Overall, studies usually only comply with 4 out of 10 of these measures, which include avoiding the use of plastic materials, covering samples with glass lids or aluminum foil, filtering solutions, or running procedural blanks. The importance of these measures is also exemplified with real observation of contamination. Finally, seven measures to control for contamination are suggested in order to improve the quality of results in microplastic sampling in future assessments.