Analysis of Microplastics in Environmental Water Using Microplastic Automatic Preparation Device MAP-100 and FTIR

Importance of Topic

Microplastic contamination in aquatic environments is a growing global issue threatening ecosystems and human health. Reliable monitoring requires thorough sample preparation to remove natural contaminants before accurate material identification. Automation enhances repeatability and safety while reducing analyst workload.

Objectives and Study Overview

This study demonstrates an automated workflow for isolating microplastics from environmental surface water using the MAP-100 device and subsequent polymer identification via FTIR spectroscopy. River water from Okinawa Prefecture was processed following national guidelines to evaluate cleaning efficiency and analytical accuracy.

Methodology and Instrumentation

The automated sample preparation comprises four consecutive steps:

• Sieving of raw specimens to remove large debris
• Oxidative digestion of organic matter with 30 % hydrogen peroxide
• Densimetric separation of inorganic contaminants using 5.3 M sodium iodide solution
• Filtration to collect microplastics in the 0.3–5 mm size range

The MAP-100 control software orchestrates these steps, provides real-time progress updates, and minimizes direct handling of hazardous reagents.

Used Instrumentation

• MAP-100 Microplastic Automatic Preparation Device
• IRSpirit™-T FTIR spectrophotometer with QATR™-S diamond ATR accessory
• Shimadzu Plastic Analyzer software package including UV-Damaged and Thermal-Damaged Plastics Library

Main Results and Discussion

After a 3-day digestion and 3-hour separation, environmental residues were effectively removed, yielding clean microplastics on the filter. FTIR analysis delivered high match scores for UV-irradiated polypropylene (PP, 876 points) and polyethylene (PE, 904 points), confirming accurate identification of weathered polymers.

Benefits and Practical Applications

• Automation reduces manual labor and variability between analysts
• Enhanced safety through limited exposure to corrosive chemicals
• High repeatability supports standardized monitoring protocols
• Accurate qualitative polymer analysis aids environmental surveys and regulatory studies

Future Trends and Opportunities

Future developments may integrate automated preparation with advanced spectroscopy and machine learning for improved detection limits and polymer classification. Expanding spectral libraries to cover novel polymer types and degradation states will enhance identification. Portable FTIR systems paired with field-deployable preparation units could enable on-site microplastic analysis.

Conclusion

The combination of the MAP-100 automated preparation platform and FTIR spectroscopy with specialized libraries offers an efficient, repeatable, and safe workflow for microplastic analysis in environmental water. This integrated approach facilitates large-scale monitoring and supports the establishment of standardized analytical methodologies.