Since microplastics are considered harmful to the human body, studies on their samplings,
pretreatments and analyses environmental media, such as water, are continuously being conducted.
However, a standard sampling and pretreatment method must be established, particularly because
microplastics of a few micrometers in size are easily affected by external contamination. In this
study, a microplastic sampling device was designed and developed to obtain a high recovery rate
of microplastics and prevent plastics contamination during all processes. For the evaluation of the
developed device, microplastic reference materials were produced and used, and computational fluid
dynamics (CFD) analysis was performed. This device has not only been applied to the relatively
large previously studied microplastics (100 m) but also to microplastics of approximately 20 m
that are vulnerable to contamination. A recovery rate of 94.2% was obtained using this device, and
the particles were separated by filtration through a three-stage cassette. In conclusion, we propose a
method to increase the accuracy and reproducibility of results for microplastic contamination in the
environment. This method is able to consistently obtain and manage microplastics data, which are
often difficult to compare using various existing methods.