Raman Tweezers for Small Microplastics and Nanoplastics Identification in Seawater

Author: Raymond Gillibert, Gireeshkumar Balakrishnan, Quentin Deshoules, Morgan Tardivel, Alessandro Magazzù, Maria Grazia Donato, Onofrio M. Maragò, Marc Lamy de La Chapelle, Florent Colas, Fabienne Lagarde and Pietro G. Gucciardi
Year of Publication: 2019
Published: Environmental Science & Technology 53, 9003-9013

Abstract:
Our understanding of the fate and distribution of micro- and nano- plastics in the marine environment is limited by the intrinsic difficulties of the techniques currently used for the detection, quantification, and chemical identification of small particles in liquid (light scattering, vibrational spectroscopies, and optical and electron microscopies). Here we introduce Raman Tweezers (RTs), namely optical tweezers combined with Raman spectroscopy, as an analytical tool for the study of micro- and nanoplastics in seawater. We show optical trapping and chemical identification of sub-20 μm plastics, down to the 50 nm range. Analysis at the single particle level allows us to unambiguously discriminate plastics from organic matter and mineral sediments, overcoming the capacities of standard Raman spectroscopy in liquid, intrinsically limited to ensemble measurements. Being a microscopy technique, RTs also permits one to assess the size and shapes of particles (beads, fragments, and fibers), with spatial resolution only limited by diffraction. Applications are shown on both model particles and naturally aged environmental samples, made of common plastic pollutants, including polyethylene, polypropylene, nylon, and polystyrene, also in the presence of a thin eco-corona. Coupled to suitable extraction and concentration protocols, RTs have the potential to strongly impact future research on micro and nanoplastics environmental pollution, and enable the understanding of the fragmentation processes on a multiscale level of aged polymers.

Keywords:
Raman, Microplastic, Nanoplastic, Seawater

Citation:
Gillibert, R., Balakrishnan, G., Deshoules, Q., Tardivel, M., Magazzù, A., Donato, M. G., Maragò, O. M., Lamy de La Chapelle, M., Colas, F., Lagarde, F., Gucciardi, P. G., 2019. Raman Tweezers for Small Microplastics and Nanoplastics Identification in Seawater. Environmental Science & Technology 53, 9003-9013.

Link:
https://doi.org/10.1021/acs.est.9b03105

Occurrence and identification of microplastics along a beach in the Biosphere Reserve of Lanzarote

Author: Carlos Edo, Miguel Tamayo-Belda, Sergio Martínez-Campos, Keila Martín-Betancor, Miguel González-Pleiter, Gerardo Pulido-Reyes, Carmen García-Ruiza, Félix Zapata, Francisco Leganés, Francisca Fernández-Piñas and Roberto Rosal
Year of Publication: 2019
Published: Marine Pollution Bulletin

Abstract:
This work studied the accumulation of plastic debris in a remote beach located in La Graciosa island (Chinijo archipelago, Canary Islands). Microplastics were sampled in the 1–5 mm mesh opening range. An average plastic density of 36.3 g/m² was obtained with a large variability along the 90 m of the beach (from 8.5 g/m² to 103.4 g/m²). Microplastic particles preferentially accumulated in the part of the beach protected by rocks. A total number of 9149 plastic particles were collected, recorded and measured, 87% of which corresponded to fragments. Clear colours and microscopic evidence of weathering corresponded to aged plastics wind-driven by the surface Canary Current. The chemical composition of plastics particles corresponded to PE (63%), PP (32%) and PS (3%). Higher PE/PP ratios were recorded in the more protected parts of the beach, suggesting preferential accumulation of more aged fragments.

Keywords:
Marine debris, marine pollution, microplastics, FTIR, Raman

Citation:
Edo, C., Tamayo-Belda, M., Martínez-Campos, D., Martín-Betancor, K., González-Pleiter, M., Pulido-Reyes, G., García-Ruiza, C., Zapata, F., Leganés, F., Fernández-Piñas, F., Rosal, R. (2019): Occurrence and identification of microplastics along a beach in the Biosphere Reserve of Lanzarote. Marine Pollution Bulletin 143:220–227

Link:
https://doi.org/10.1016/j.marpolbul.2019.04.061