Validation of an optimised protocol for quantification of microplastics in heterogenous samples: A case study using...

Area of Science:

• Marine Biology
• Environmental Science
• Analytical Chemistry

Background:

• Quantifying microplastic (<5 mm) contamination in marine ecosystems is critical.
• Existing microplastic extraction methods are often unsuitable for heterogeneous biological samples like marine fauna gastro-intestinal content.
• Developing reliable extraction techniques is essential for assessing microplastic ingestion in marine animals.

Purpose of the Study:

• To present a novel, validated microplastic extraction protocol specifically for green turtle (Chelonia mydas) chyme.
• To address the challenge of extracting microplastics from heterogeneous biological matrices.
• To enable accurate and comparable quantification of microplastic contamination in marine turtles.

Main Methods:

• Modification and combination of established extraction techniques.
• Acid digestion to remove organic matter.
• Emulsification of residual fats.
• Density separation to isolate microplastics from sediment.
• Fourier-transform infrared (FTIR) spectroscopy for chemical identification.

Main Results:

• The protocol effectively extracts common microplastics (>100 μm) including polyethylene, high-density polyethylene, (aminoethyl) polystyrene, polypropylene, and polyvinyl chloride.
• Achieved 100% extraction efficiency for these target microplastics.
• Demonstrated effectiveness for heterogeneous samples containing both organic and inorganic materials.

Conclusions:

• The developed protocol offers a reliable and comparable method for quantifying microplastic contamination in green turtles.
• This validated technique will aid researchers globally in assessing microplastic burdens in marine fauna.
• Optimized microplastic extraction from complex biological samples is achievable through sequential application of established methods.