Development of robust models for rapid classification of microplastic polymer types based on near infrared hyperspectral images. Issue 19 (28th April 2021)

• Record Type: Journal Article
• Authors: Kitahashi, Tomo; Nakajima, Ryota; Nomaki, Hidetaka; Tsuchiya, Masashi; Yabuki, Akinori; Yamaguchi, Sojiro; Zhu, Chunmao; Kanaya, Yugo; Lindsay, Dhugal J.; Chiba, Sanae; Fujikura, Katsunori
• Is Part Of: Analytical methods. Volume 13:Issue 19(2021)
• Page Start: 2215
• Page End: 2222
• Publication Date: 2021-04-28
• Subjects: Chemistry, Analytic -- Periodicals; Analytical biochemistry -- Periodicals; Chemical laboratories -- Standards -- Periodicals; 543.1905
• DOI: 10.1039/d1ay00110h
• Languages: English
• ISSNs: 1759-9660

Abstract

Abstract : Robust models that are capable of classifying polymer types could be built based on HSI data for small particles measured on wet filters. HSI techniques with appropriate models allow the rapid identification of microplastics. Abstract : Hyperspectral data in the near infrared range were examined for nine common types of plastic particles of 1 mm and 100–500 μm sizes on dry and wet glass fiber filters. Weaker peak intensities were detected for small particles compared to large particles, and the reflectances were weaker at longer wavelengths when the particles were measured on a wet filter. These phenomena are explainable due to the effect of the correlation between the particle size and the absorption of infrared light by water. We constructed robust classification models that are capable of classifying polymer types, regardless of particle size or filter conditions (wet vs. dry), based on hyperspectral data for small particles measured on wet filters. Using the models, we also successfully classified the polymer type of polystyrene beads covered with microalgae, which simulates the natural conditions of microplastics in the ocean. This study suggests that hyperspectral imaging techniques with appropriate classification models allow the identification of microplastics without the time- and labor-consuming procedures of drying samples and removing biofilms, thus enabling more rapid analyses.