Microplastics Analysis by FTIR and Raman

Small particles. Big impact.

Beaches, clothing, bottled water, fish, beer, the air and honey all have one thing in common. They each contain microplastics.

Entering your local convenience store, you assume purified bottled water is free from harmful particles. Surprisingly, bottled water is no exception to microplastics contamination and, in fact, has higher contamination than tap water. Research at the State University of New York at Fredonia showed that 93% of tested bottled water had microplastics contamination [4]. This has prompted the World Health Organization (WHO) to evaluate all available research on microplastics to help understand whether a lifetime of eating and drinking microplastics could have an effect on human health. Unfortunately, microplastics are not being detected in water purification systems, so they can come from the tap water sources as well as being created from the machinery during the bottling process. This presents a potential liability risk for beverage companies who are just now exploring how best to measure microplastics in their products.

Uncanny health effects

The impact to human health of microplastics contamination is currently unknown as the discovery is relatively new. This means we must find ways to study the composition and prevalence of microplastics as well as their biological and toxicological effects on humans.

Microplastics analytical problem

To distinguish these microparticles, the current strategy is to use a stereo-microscope and tediously separate microplastics from other materials. [6] Unfortunately this visual method is prone to errors due to the extremely small size (<1 mm) of microplastics and the potential for human error and sample contamination. This near-impossible and time-consuming identification process leaves us with a challenging problem.

The analytical solution

Raman and infrared microscopy can provide the proper identification of a wide range of microplastic particles (1-5000 µm diameter) collected from environmental, industrial, municipal or consumer-product samples.  These techniques use the ability of light to interact with molecules causing them to vibrate at given frequencies. As a result, a spectrum (or a peak pattern of absorbed or emitted frequencies - Figure 2) can provide a “molecular fingerprint” of a microparticulate, providing the identity of its components.

For particles >1 μm, the Thermo Scientific DXR3xi Raman Imaging Microscope offers the analytical power to discern microplastics from other contaminants with high-spatial resolution down to 0.5 µm. The  multivariate analysis algorithms of the Thermo Scientific OMNIC Software allows for spectral identification across a spectral library of plastics and polymers. The DXR3xi Raman Microscope has autoalignment and calibration capabilities to ensure accurate measurements and consistency between operators, supporting recommendations made by the EPA working group. This microscope quickly images large surface areas across the sample filter, making it a fast, reliable method for comparing multiple particulates and identifying their chemical components. For microplastic particles >10 μm, the Thermo Scientific Nicolet iN10 MX FTIR Imaging Microscope offers similar chemical imaging capabilities with speed and efficiency.

References

1. https://marinedebris.noaa.gov/sites/default/files/publications-files/TM_NOS-ORR_30.pdf
2. https://orbmedia.org/stories/Invisibles_plastics
3. https://www.theguardian.com/environment/2017/sep/06/plastic-fibres-found-tap-water-around-world-study-reveals
4. https://orbmedia.org/stories/plus-plastic/
5. https://www.theguardian.com/lifeandstyle/2017/feb/14/sea-to-plate-plastic-got-into-fish
6. https://www.epa.gov/trash-free-waters/microplastics-expert-workshop-report
7. https://www.nature.com/articles/srep03263

The sample workflow diagram in Figure 3 shows a typical process, from sample preparation to microplastics analysis.

Literature

Common Plastics Identifiable by FTIR and Raman Spectroscopy

Citations

Find peer reviewed publications using FTIR and Raman spectroscopy for microplastics analysis.

What is your opinion of the current state of microplastics pollution as a problem and how much work is needed to better understand the extent of the problem?

The microplastics issue is at the stage where investigations have been implemented worldwide in earnest this year. Big projects have already launched to standardize measurements/determine finer microplastics for a unified analytical solution. In addition, the research of degradation of conventional plastics or biodegradable plastics in the environment field have also been started. Perhaps, a related report will publish in a couple of years as well, then I expect specific regulations will be launched globally.

What is your research focus?

• Analytical solution development and monitoring for ultra-fine microplastics (0.1 μm to 20 μm) in the environment
• Elucidation of sources and movement mechanisms and weathering phenomena of global microplastics in the ocean, including ecological impact assessment

What sinks (lakes/oceans/etc…) are you evaluating?

Target samples are: tap water, seawater, sandy beach, food, biodegradable plastic, and living drainage

What specifically are you trying to understand?

I am interested in the following points

• Determining the concentration of microplastics in the ocean including very fine particles in 0.1-20 μm size range and the prediction of future concentration as well as particle size distribution.
• Determination of the degree of weathered microplastics

What does your sampling and analysis workflow look like? What are the key challenges associated with trying to analyze microplastics in environmental samples?

At present, development of a solution for sampling and analyzing >20 μm microplastics has been completed, it is now in the commercialization stage. Detailed methods will be published soon, but a brief explanation is as follows,

• Collect samples using plastic-free equipment
• Pretreatment using hydrogen peroxide, sodium iodide and enzyme
• Automatic analysis by Thermo Scientific Nicolet iN10 MX Infrared Imaging Microscope with automatic particle analysis software. For particles <20 μm, this is currently my key research. My problems in method development are likely to be resolved. I am currently searching for a Raman supplier as a partner for the development. I am planning to develop the analysis method with Raman into 2021.

What kind of instrumentation do you use? How useful is it to have more automated solutions for microplastics location and identification?

I am using a Nicolet iN10MX Microscope to define particle size, identification and quantification with OMNIC Picta software.

What is your opinion on the current state of regulations? Are you engaged with regulatory leaders? What are your expectations of national and international regulations on microplastics pollution and monitoring?

• Microplastic contamination and pollution characteristics are still not known. Sometimes I work with key regulators.  In the future, I expect the investigation of microplastics, as well as policies to control microplastic pollution, will be implemented as follows:
• The environmental surveys will be conducted for microplastics down to a limit of 20 or 0.2 μm particles (currently the limit can be >300 μm).
• Polymers that are highly toxic in the environment and that are likely to exist as microparticles in the environment may be banned.
• It will be recommended to use and adopt biodegradable plastics. At that time, the environmental degradation test would be revised to measure the particle size distribution. As a result, with these new definitions, conventional biodegradable plastics may not meet the requirements.
• The polymers of microcapsules used in daily necessities are also likely to be replaced with new materials.

Contact us

Bio: Dr. Yutaka Kameda | Chiba Institute of Technology | Associate Professor

Education
1998 – 2000: Hokkaido University, PhD in Environment and Resources Engineering
1995 – 1997: Tohoku University, MSc in Water Engineering
1991– 1994: Tohoku University, BSc in Civil Engineering

Work Experience
2012 – Present: Associate professor of creative engineering, Chiba Institute of Technology
2007 – 2012: Researcher in Water Environment, Center for Environment Science in Saitama
2006 – 2007: Researcher, Public Works Research Institute, Japanese government
1992 – 2005: COE fellow, Environmental Risk lab, Yokohama National University

Research Projects

• Microplastics monitoring and their environmental behavior analysis in western Pacific Ocean. (Grants‐in‐aid for Scientific Research, Japanese government)
• Establishment of novel analysis methods to measure microplastics by micro-FTIR spectroscopy (Thermo Fisher Scientific)
• Microplastics monitoring, their environmental behavior analysis and establishment of their simulation models in Japanese rivers. (Japanese River Fund)
• Developing new tools for evaluating the environmental impact of emerging organic chemicals on coastal environments and organisms. (The Foundation for Australia-Japan Studies)
• Neonicotinods exposure pathway analysis to bee colonies and honey in Japan (Actbeyond Foundation)

Recent Papers

1. D. Ueno, H. Mizukawa, O. Inanami, H. Nagasaka, N. Tatsuta, Y. Narazaki, T. Fujino, I. Watanabe, Y. Kameda, K. Nakai：“Caddisfly watch”, a biomonitoring program using Stenopsyche larvae to determine radioactive cesium contamination in rivers following the Fukushima nuclear disaster, Landscape and Ecological Engineering, January 2018, Volume 14, Issue 1, pp29-35
2. M. Allinson, Y. Kameda, K. Kimura and G. Allinson: Occurrence and assessment of the risk of ultraviolet filters and light stabilizers in Victorian estuaries, Environmental Science and Pollution Research, April 2018, Volume 25, Issue 12, pp12022-12033
3. Y. Tashiro, Y. Kameda: Pesticide Contamination Monitored by Passive Sampling in Environmental Water of Japanese Coral Island, Journal of Water Resources and Ocean Science; 2015;4(2):39-43 (Mar, 2015)

Sample preparation kit/consumables

Getting supplies and samples ready for microparticle analysis can be cumbersome. These microparticle analysis sample preparation kits are here to help streamline the process, no matter your sample type.

Learn more

Instrument bundles

•  FTIR Microplastics Analyzer Bundle
•  Raman Microplastics Analyzer Bundle

Instrumentation

	FTIR + ATR	FTIR + Small Spot ATR	Point-and-Shoot FTIR Microscope	FTIR Imaging Microscope	Raman Microscope	Raman Imaging Microscope
Configuration
	Nicolet Summit PRO FTIR Spectrometer and Everest ATR Accessory	SurveyIR Microspectroscopy Accessory + Nicolet Summit PRO FTIR Spectrometer	Nicolet iN5 IR Microscope + Nicolet Apex FTIR Spectrometer	Nicolet iN10 MX IR Imaging Microscope	DXR3 Raman Microscope	DXR3xi Raman Imaging Microscope
Measurable Particle Size
5 mm	✓
1 mm	✓	✓
500 μm	✓	✓
100 μm		✓	✓	✓
10 μm			✓	✓	✓	✓
1 μm					✓	✓
Manual Sample Placement Only	Yes	Yes	Yes	No	No	No
Automated Analysis of Filters	No	No	No	Yes	Yes	Yes
Immunity to Sample Fluorescence	Yes	Yes	Yes	Yes	No	No