Identification of microplastics in a large water volume by integrated holography and Raman spectroscopy

Tomoko Takahashi* (Corresponding Author), Zonghua Liu, Thangavel Thevar, Nicholas Burns, Sumeet Mahajan, Dhugal Lindsay, John Watson, Blair Thornton

*Corresponding author for this work

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A noncontact method to identify sparsely distributed plastic pellets is proposed by integrating holography and Raman spectroscopy in this study. Polystyrene and poly(methyl methacrylate) resin pellets with a size of 3 mm located in a 20 cm water channel were illuminated using a collimated continuous wave laser beam with a diameter of 4 mm and wavelength of 785 nm. The same laser beam was used to take a holographic image and Raman spectrum of a pellet to identify the shape, size, and composition of material. Using the compact system, the morphological and chemical analysis of pellets in a large volume of water was performed. The reported method demonstrates the potential for noncontact continuous in situ monitoring of microplastics in water without collection and separation.
Original languageEnglish
Pages (from-to)5073-5078
Number of pages6
JournalApplied Optics
Issue number17
Early online date2 Jun 2020
Publication statusPublished - 10 Jun 2020

Bibliographical note

Japan Science and Technology Agency SICORP (JPMJSC1705); Natural Environment Research Council (NE/R01227X/1); Kajima Foundation (Overseas research grant); Japan Society for the Promotion of Science (18H03810, 18K13934); Kurita Water and Environment Foundation (17B030).


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