Quantitative analysis of microplastics in seawater based on SERS internal standard method

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Microplastics pose health risks, entering the human body via the food chain and potentially causing cardiovascular and cerebrovascular diseases.
• Traditional microplastic detection methods lack sensitivity, especially for particles under 1 μm, and involve complex procedures.
• Surface-Enhanced Raman Scattering (SERS) offers improved sensitivity but has limited application in quantitative microplastic analysis.

Purpose of the Study:

• To develop a sensitive and accurate method for qualitative and quantitative detection of microplastics.
• To optimize SERS substrates for enhanced electric field effects and improved detection limits.
• To establish a reliable method for microplastic analysis in environmental samples like seawater.

Main Methods:

• Utilized Surface-Enhanced Raman Scattering (SERS) combined with an internal standard method for microplastic detection.
• Employed finite element method simulations to analyze electric field enhancement on gold, silver, and copper substrates, optimizing structural parameters.
• Fabricated a gold nanopyramid array substrate using the colloidal sphere template method for enhanced SERS performance.

Main Results:

• Successfully detected 500 nm polystyrene microplastics with a detection limit of 1.8 × 10⁻⁴ mg mL⁻¹.
• Achieved a wide quantitative range of 2-2 × 10⁻⁴ mg mL⁻¹ with a high linear regression correlation coefficient (0.9918).
• Demonstrated a lower detection limit and broader quantitative range compared to traditional methods.

Conclusions:

• The developed SERS method provides a sensitive and accurate approach for microplastic detection.
• The optimized gold nanopyramid array substrate enhances SERS performance for microplastic analysis.
• This study expands possibilities for qualitative and quantitative microplastic detection in environmental matrices, particularly seawater.