Stimulated Raman microspectroscopy as a new method to classify microfibers from environmental samples. (December 2020)

• Record Type: Journal Article
• Authors: Laptenok, Sergey P.; Martin, Cecilia; Genchi, Luca; Duarte, Carlos M.; Liberale, Carlo
• Is Part Of: Environmental pollution. Volume 267(2020)
• Publication Date: 2020-12
• Subjects: Microfibers -- Microplastic -- Stimulated Raman scattering -- SRS microscopy -- Vibrational microspectroscopy; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2020.115640
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Microfibers are reported as the most abundant microparticle type in the environment. Their small size and light weight allow easy and fast distribution, but also make it challenging to determine their chemical composition. Vibrational microspectroscopy methods as infrared and spontaneous Raman microscopy have been widely used for the identification of environmental microparticles. However, only few studies report on the identification of microfibers, mainly due to difficulties caused by their small diameter. Here we present the use of Stimulated Raman Scattering (SRS) microscopy for fast and reliable classification of microfibers from environmental samples. SRS microscopy features high sensitivity and has the potential to be faster than other vibrational microspectroscopy methods. As a proof of principle, we analyzed fibers extracted from the fish gastrointestinal (GIT) tract, deep-sea and coastal sediments, surface seawater and drinking water. Challenges were faced while measuring fibers from the fish GIT, due to the acidic degradation they undergo. However, the main vibrational peaks were still recognizable and sufficient to determine the natural or synthetic origin of the fibers. Notably, our results are in accordance to other recent studies showing that the majority of the analyzed environmental fibers has a natural origin. Our findings suggest that advanced spectroscopic methods must be used for estimation of the plastic fibers concentration in the environment. Graphical abstract: Image 1 Highlights: Ubiquitous environmental microfibers are challenging to classify due to their small size. Stimulated Raman Scattering Microscopy reliably classifies environmental microfibers. Spectroscopic methods are essential for classification of environmental microfibers. Majority of the analyzed environmental microfibers are attributed to natural origin. Abstract : Capsule: We present Stimulated Raman Microscopy as a new method to reliably classify environmental microfibers. The majority of analyzed microfibers were of natural origin.