Approaches for Sampling and Sample Preparation for Microplastic Analysis in Laundry Effluents

The continuous growth in the production, unsustainable use, and disposal of plastics in recent decades has led to the emergence of a new type of pollutant, microplastics (MPs). In this article, the focus is on the form of MPs, which are produced by the fragmentation of textile fibres during washing processes. The problems associated with the characterisation and quantification of MPs in this type of sample are related to the wide range of concentrations, forms, and degree of degradation as well as physico-chemical and biological properties. Although the basic principles for the analysis of microplastics present in the environmental samples are known, there is the lack of standardised methods for the analysis of MPs in laundry effluents and domestic washing. Therefore, the continuous development of sophisticated analytical techniques and methodologies is required for the reliable collection and isolation, quantification, and characterisation of one of the most challenging analytes. The aim of this review is to outline the key steps of MPs analysis in laundry effluents and domestic washing, focusing on those steps that are underestimated in the current literature: sampling and sample preparation for analysis. Precisely these analytical steps, which can become the main source of analytical measurement system errors, ensure the quality of the analysis. This paper emphasises the importance of monitoring background contamination and presents guidelines to ensure quality control specifically for this type of analyte.