Scientists Develop Cost-Effective Raman System for Microplastic Detection

Environmental sustainability is an important topic in the scientific community. Because of Earth’s growing population, especially in third-world countries, issues such as pollution have become crises in certain pockets of Earth. Our sister publication, LCGC International, covered this particular issue in depth, spotlighting a few cities around the world struggling to control their pollution, one of which was Delhi, India (1).

Some of the main culprits that are negatively impacting the environment are microplastics (MPs), which are plastic particles that range from 1 µm to 5 mm in size (2). A recent study, led by Jijo Lukose at the Centre of Excellence for Biophotonics, Department of Atomic and Molecular Physics, Manipal Academy of Higher Education, demonstrated the utility of a newly developed micro-Raman spectroscopy system (2). The objective of this study was to show that this new system overcomes some of the main limitations of other micro-Raman spectroscopy systems, which is its accessibility and cost-effectiveness.

Microplastics. Male hands holding a test tube containing microplastic fragments and dirt on a lake. Plastic pollution and industrial waste management. environment. | Image Credit: © Pcess609 - stock.adobe.com

Microplastics cause potential harm to ecosystems, especially marine organisms (3). Marine organisms often ingest these tiny particles, resulting in physical injuries or blockages and the transfer of toxic substances through the food chain (3). Humans are exposed to microplastics through contaminated seafood and water, yet the full extent of their health effects remains unclear (2).

Although commercial Raman spectroscopy platforms are widely used to identify microplastics, their high costs make them inaccessible to many research institutions in developing nations. Lukose emphasizes the need for indigenous alternatives to tackle this issue effectively (2). The research, conducted along the shores of Malpe Beach in Udupi district, Karnataka, revealed the presence of microplastics such as polyethylene (PP) and polyethylene terephthalate (PET) in water samples (2). Pigments like copper phthalocyanine and indigo blue were also detected, highlighting the widespread contamination of waterbodies by synthetic materials (2).

There are numerous features in the micro-Raman spectroscopy system developed by the team that are worth pointing out. As an example, experimental parameters helped ensure reproducible and accurate results (2). These experimental parameters include laser power, exposure time, and accumulation rates. The research team also made a standardized Raman spectral database for different types of plastics, which ensured reliable identification of microplastic particles in environmental samples (2).

To test their system, the researchers used principal component analysis (PCA) to confirm the method’s effective classification of various plastic types, confirming its utility as a research and monitoring tool (2). This analytical approach further underscores Raman spectroscopy's advantages over traditional polymer identification methods (2).

This research underscores the urgency of equipping nations with the means to study and address microplastic pollution (2). Lukose and his team at the Manipal Academy of Higher Education proposed a method that provides a pathway to democratize environmental research, empowering local researchers to combat pollution with tailored, affordable technologies (2).

Beyond the immediate scope of microplastic analysis, the study highlights the versatility of Raman spectroscopy. As a non-destructive technique capable of probing the chemical structure of materials, Raman spectroscopy has broader applications in fields ranging from pharmaceuticals to forensic science (2,4). Its adoption for environmental monitoring reflects the growing demand for robust analytical tools in addressing global sustainability challenges.

Although the custom-built micro-Raman spectroscopy system represents a significant leap forward, Lukose and his team are focused on refining the technology and expanding its accessibility. They aim to collaborate with environmental agencies and academic institutions to standardize protocols and scale the system for broader use (2). Because their device is inexpensive and workable, the researchers are helping to find new ways to classify microplastics and safeguard the environment.

References

1. Wetzel, W. The Critical Role of Chromatography in Addressing Urban Air Pollution. LCGC International. Available at: https://www.chromatographyonline.com/view/the-critical-role-of-chromatography-in-addressing-urban-air-pollution (accessed 2024-11-19).
2. Sunil, M.; N, M.; Charles, M.; et al. Visualization and Characterisation of Microplastics in Aquatic Environment Using a Home-Built Micro-Raman Spectroscopic Set Up. J. Environ. Man. 2024, 354, 120351. DOI: 10.1016/j.jenvman.2024.120351
3. Lee, Y.; Cho, J.; Sohn, J.; Kim, C. Health Effects of Microplastic Exposures: Current Issues and Perspectives in South Korea. Yonsei Med. J. 2023, 64 (5), 301–308. DOI: 10.3349/ymj.2023.0048
4. Workman, Jr., J. How Raman Spectroscopy Could Transform Hematology Diagnostics. Spectroscopy. Available at: https://www.spectroscopyonline.com/view/how-raman-spectroscopy-could-transform-hematology-diagnostics (accessed 2024-11-19).