Technique for Measuring Microplastics Collected on Various Filters Using a Particle Filter Holder

User Benefits

- Particle filter holders provide clear microscope images of samples, enabling highly accurate measurements. - Microplastics can be analyzed accurately and efficiently by using a particle filter holder with a high-speed mapping program and a particle analysis program.

Introduction

Since microplastics (MPs) (with diameters ranging from a few μm up to 5 mm) are widely recognized as an environmental problem in marine environments, Japan’s Ministry of the Environment has issued guidelines for preparation and measuring MPs in environmental surface waters. The guidelines include examples of using a Fourier transform infrared spectrophotometer (FTIR) to identify plastics by the total reflectance measurement method. However, to identify fine MPs, they recommend using instruments like infrared microscopes. In recent years, an increasing number of studies have analyzed fine MPs smaller than 100 μm. Measuring MPs with an infrared microscope requires collecting samples on a filter. Various types of filters can be used for infrared microscopes, each with unique characteristics. But if a filter cannot be held horizontal during drying or measuring, it can develop wrinkles that might decrease measurement accuracy. Therefore, a particle filter (PF) holder was developed that can be placed directly on an infrared microscope stage while holding the filter horizontally. This article describes using the IRXross Fourier transform infrared spectrophotometer, an AIMsight infrared microscope, and a PF holder to evaluate the properties of various filters and measure a standard sample of MPs.

January 13, 2026 GMT