Py-GC-MS/MS quantification of microplastics in vertebrate tissues: Addressing false positives of polyethylene

Area of Science:

• Environmental Science
• Ecotoxicology
• Analytical Chemistry

Background:

• Rising plastic production leads to widespread environmental contamination.
• Vertebrate exposure to microplastics, especially small microplastics (SMPs), is increasing.
• Reliable quantification of SMPs in wildlife tissues is challenging, limiting impact assessment.

Purpose of the Study:

• To develop and validate a method for quantifying SMPs in vertebrate tissues.
• To measure SMP concentrations in the gastrointestinal tract of the Yellow-legged Gull (Larus michahellis).
• To establish a foundation for understanding microplastic impacts on wildlife.

Main Methods:

• Developed a novel quantification method using pyrolysis gas chromatography coupled with tandem mass spectrometry (Py-GC/MS-MS).
• Optimized sample preparation, including potassium hydroxide digestion, for four gastrointestinal organs.
• Employed specific long-chain markers to overcome lipid interference in polyethylene quantification.

Main Results:

• The Py-GC/MS-MS method achieved limits of quantification (LOQs) of 1-50 µg/g for various plastic types (PE, PMMA, PP, PS, PET).
• Microplastic concentrations in Yellow-legged Gull digestive tissues ranged up to several hundred µg/g dry weight.
• One gull exhibited exceptionally high exposure levels to polystyrene (PS) and polyethylene (PE).

Conclusions:

• The developed Py-GC/MS-MS method provides reliable quantification of SMPs in complex biological matrices.
• This technique enables accurate assessment of microplastic burdens in wildlife.
• Findings underscore the significant microplastic exposure in seabirds and the need for further toxicological research.