Microplastics Characterization in Carbonated Beverages and Apple Juice by Laser Direct Infrared

Importance of the Topic

Plastic contamination in food and beverages is a growing health and environmental concern. Carbonated drinks and juices packaged in plastic, glass, metal, or cartons may shed microplastics that consumers ingest. There is an urgent need for rapid, reliable methods to monitor these contaminants in complex liquid matrices and support quality control.

Objectives and Study Overview

The study applied the Agilent 8700 Laser Direct Infrared (LDIR) chemical imaging system to detect and characterize microplastics in commercial carbonated beverages and apple juice. It aimed to develop a robust, high-throughput workflow that minimized sample preparation and maximized analytical confidence across various packaging types.

Methodology and Instrumentation

Samples were directly filtered onto aluminum-coated polyester membranes. Carbonated samples were degassed and filtered in one step, while apple juice required a prefiltration step to remove subvisible particulates. A two-position filter holder enabled sequential analysis of blanks and samples to control contamination. The Agilent 8700 LDIR, featuring a quantum cascade laser and high-resolution visible cameras, performed automated particle detection and spectral acquisition across the mid-infrared region. Analysis employed the Particle Analysis method in Agilent Clarity software with the built-in microplastics library.

Main Results and Discussion

Microplastics were detected in all beverage samples with high confidence (Hit Quality Index >0.85). In carbonated drinks, PVC and PET were the most abundant polymers, with counts ranging from tens to hundreds of particles per sample, depending on packaging. Glass containers exhibited unexpectedly high PVC levels, possibly from cap liners. In apple juice, carton-packaged samples yielded mainly polyethylene particles, while PET bottles released primarily PET fragments. The residue on filters did not interfere with particle identification.

Benefits and Practical Applications

• Reduced sample preparation simplifies workflow and lowers contamination risk.
• Direct on-filter analysis enables complete filtration of product volume.
• Automated detection and identification with Agilent Clarity ensures consistent, high-throughput results.
• Quantitative and qualitative data support quality control and regulatory compliance.

Future Trends and Opportunities

Advancements in infrared imaging and spectral libraries will enhance detection limits and polymer specificity. Integration with machine learning could automate anomaly detection and trend analysis. Expanded applications may include monitoring microplastics in diverse food matrices and real-time inline process control during manufacturing.

Conclusion

The Agilent 8700 LDIR system offers a fast, automated, and reliable platform for microplastic analysis in beverages. Its direct-on-filter approach combined with robust quality control provides comprehensive chemical and physical characterization of particles, facilitating risk assessment and regulatory monitoring in the food industry.

References

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