Fast identification of microplastics in complex environmental samples by a thermal degradation method

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Microplastic pollution requires reliable analytical methods for environmental monitoring.
• Current methods like optical spectroscopy and Py-GC-MS have limitations in speed, sample size, and applicability to complex environmental matrices.
• Accurate identification and quantification of microplastics are crucial for understanding their environmental relevance.

Purpose of the Study:

• To develop a novel thermoanalytical method for the initial identification of microplastics in environmental samples.
• To overcome the limitations of existing analytical techniques for microplastic analysis.
• To screen environmental samples for the presence of common microplastic polymers.

Main Methods:

• A new thermoanalytical method involving complete thermal decomposition of a larger sample amount (approx. 20 mg).
• Adsorption of specific polymer degradation products onto a solid-phase adsorber.
• Analysis of adsorbed products using thermal desorption gas chromatography mass spectrometry (TD-GC-MS).
• Selection of characteristic degradation products for polymer identification.

Main Results:

• The developed method successfully screened environmental samples from aquatic (rivers) and terrestrial (biogas plant) systems.
• Polypropylene (PP), polyethylene (PE), and polystyrene (PS) were identified in biogas plant samples.
• PE and PS were detected in river water samples.
• The method demonstrated potential for analyzing complex environmental matrices.

Conclusions:

• The new thermoanalytical method offers a promising first step for microplastic identification in environmental samples.
• It addresses limitations of existing methods by allowing analysis of larger sample sizes and complex mixtures.
• Further quantification studies are planned to build upon these initial identification results.