A multimodal Raman - XRF approach for identifying marine coating microplastics in environmental samples

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Marine coatings are an understudied source of microplastic pollution in oceans.
• Distinguishing coating microplastics from conventional plastics is challenging due to similar physical and spectral properties.

Purpose of the Study:

• To develop and validate a combined Raman spectroscopy and X-ray fluorescence (XRF) approach for identifying and classifying marine coating microplastics.
• To differentiate coating-derived microplastics from other common microplastic types in marine environments.

Main Methods:

• Utilized Raman spectroscopy for organic vibrational signature analysis.
• Integrated X-ray fluorescence (XRF) for elemental composition analysis.
• Applied Principal Component Analysis (PCA) to spectral data for classification.

Main Results:

• Raman spectroscopy alone showed spectral overlap, limiting accurate classification of coatings.
• Integrating XRF elemental data with Raman spectra significantly improved the separation and classification of epoxy, antifouling, anticorrosive, and topcoat materials.
• The combined method accurately distinguished copper-rich, zinc-based, epoxy, and topcoat coatings, overcoming limitations of single-technique analysis.

Conclusions:

• The combined Raman spectroscopy and XRF approach provides a robust method for identifying and classifying marine coating microplastics.
• This multimodal technique enhances accuracy in microplastic source attribution and environmental monitoring.
• Portable instruments allow for feasible field application, aiding in the assessment and mitigation of coating-derived microplastic pollution.