Analytical method development for nano-plastics in seawater : Concentration by using ultra-filtration and chemical characterization

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K22906
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 63:Environmental analyses and evaluation and related fields
• Research Institution: Tokyo University of Agriculture and Technology
• Principal Investigator: Hideshige Takada 東京農工大学, (連合)農学研究科(研究院), 教授 (70187970)
• Co-Investigator(Kenkyū-buntansha): 小川 浩史 東京大学, 大気海洋研究所, 教授 (50260518)
• Project Period (FY): 2019-06-28 – 2021-03-31
• Keywords: プラスチック汚染 / ナノプラスチック / マイクロプラスチック / 限外ろ過 / 熱分解GC-MS

Outline of Final Research Achievements

Analytical method of nanoplastics in seawater has been developed as follows. One hundred liter of seawater was collected in stainless-steal container, transported to laboratory, and filtered by glass fiber filter (GF/F). The filtrate was ultra-filtered by using hollow fiber membrane and concentrated by freeze-dryer down to ~ hundreds mL. The colloidal aqueous solution was subjected to oxidation with hydrogen peroxide and hydrolyzed with potassium hydroxide. Nanoplastics were partitioned into hexane and subjected to gel-permeation chromatography. Polymer fraction was injected to pyrolysis-GC/MS and polyethylene (PE) and polystyrene (PS) was monitored on SIM mode at m/z = 83 and m/z = 91, respectively. No nanoplastics were significantly detected (PS < 0.4 ng/L) in the 100 L of seawater.

Free Research Field

環境化学

Academic Significance and Societal Importance of the Research Achievements

ナノプラスチックの計測法を開発して、今後の実試料での測定の可能性を示した。東京湾の海水100Lを分析した場合、ナノポリスチレンのピークは観測されたが、ブランクに対して有意ではなく、ナノポリスチレンが存在したとしても濃度は0.4 ng/L以下ということが推察された。今後の環境試料での実測を進める上で意義がある成果と考えられる。