Impacts of temperature and selected chemical digestion methods on microplastic particles

Area of Science:

• Environmental chemistry
• Polymer science
• Analytical chemistry

Background:

• Microplastic contamination is a growing environmental concern.
• Accurate quantification and identification of microplastics are crucial for environmental risk assessment.
• Chemical digestion methods are commonly used to isolate microplastics from complex organic matrices.

Purpose of the Study:

• To evaluate the effectiveness of alkaline and wet peroxide oxidation digestion techniques for microplastic extraction.
• To assess the impact of these methods on polymer recovery rates.
• To determine the influence of digestion methods on the ability to identify polymer types using Fourier transform infrared spectroscopy (FT-IR).

Main Methods:

• Microplastics were extracted from organic matrices using alkaline and wet peroxide oxidation.
• Recoveries of different microplastic types were quantified.
• Polymer identification was performed using FT-IR.
• Boiling tests were conducted to determine temperature thresholds for microplastic loss.

Main Results:

• Wet peroxide oxidation led to significant losses of certain microplastic types due to elevated temperatures (>70°C).
• Alkaline digestion demonstrated better retention of microplastic particles.
• FT-IR analysis confirmed minimal chemical alteration of recovered polymers by both digestion methods.

Conclusions:

• Wet peroxide oxidation is not suitable for microplastic extraction when high temperatures are involved, as it can lead to particle loss.
• Alkaline digestion is a more reliable method for microplastic extraction from organic matrices, preserving particle integrity for identification.
• FT-IR is a robust technique for confirming polymer identity after chemical digestion.