Agilent 8700 LDIR Chemical Imaging System (Recent Publications)

Significance of the Topic

The proliferation of microplastics across environmental and biological matrices poses critical challenges for pollution monitoring, regulatory compliance, and human health risk assessment. High-throughput, reliable analytical methods such as laser direct infrared (LDIR) imaging address the need for rapid polymer identification and precise quantification, enabling researchers and laboratories to evaluate contamination trends and treatment efficiencies accurately.

Objectives and Study Overview

This compilation reviews recent studies employing the Agilent 8700 LDIR Chemical Imaging System to detect, identify, and quantify microplastics in marine, freshwater, soil, wastewater, drinking water, food, and biological samples. It highlights methodological advancements, performance comparisons with established vibrational spectroscopy techniques, and applications in diverse matrices.

Methodology and Instrumentation

LDIR imaging integrates a tunable quantum cascade laser with automated particle recognition to acquire full infrared spectra of particles down to ~20 μm in diameter. Samples are deposited on infrared-transparent substrates (e.g., Kevley slides) or filters, then scanned to categorize polymer type, size, and morphology. Analysis times for hundreds to thousands of particles typically range from 1 to 3 hours, significantly reducing post-processing compared to FTIR or Raman hyperspectral imaging.

Used Instrumentation

• Agilent 8700 Laser Direct Infrared (LDIR) Chemical Imaging System
• Complementary techniques in many studies: ATR-FTIR microscopy, Raman spectroscopy

Main Results and Discussion

Across reviewed publications, LDIR consistently achieved high identification accuracy (>97% match to reference spectra) and recovery rates of 80–100% for common polymers (PP, PE, PS, PVC, PET). Key findings include:

• Marine environments: Spatial mapping in oceans and estuaries revealed polymer distributions linked to freshwater inflows, depth, and hydrodynamic transport.
• Soils and sediments: Quantification in agricultural lands showed microplastic accumulation correlated with film mulching duration and land use practices.
• Wastewater and treatment plants: Long-term monitoring demonstrated removal efficiencies, method comparisons (LDIR vs. optical microscopy), and contributions of laundry-derived microfibers.
• Drinking water and food: Bottled water studies detected MPs in 94% of brands; feeding bottles and injectors released microplastics during normal use.
• Biological samples: Detection of MPs in human sputum, placentas, infant tissues, fish gastrointestinal tracts, indicating exposure pathways and potential health impacts.

Benefits and Practical Applications of the Method

LDIR imaging offers:

• High throughput with automated particle counting and polymer typing.
• Low detection limits (~20 μm) and minimal operator bias.
• Compatibility with environmental monitoring, QA/QC in industrial and clinical laboratories.
• Rapid data processing, facilitating large-scale temporal and spatial studies.

Future Trends and Opportunities for Use

Emerging directions include:

• Integration of machine learning and deep learning for spectrum classification and sub-20 μm detection.
• Standardization of LDIR protocols across laboratories and matrices.
• Coupling LDIR with microdissection pressure catapulting (LMPC) for single-particle validation.
• Extension to nano-plastic analysis and incorporation into routine environmental surveillance.

Conclusion

The Agilent 8700 LDIR system has proven to be a robust, efficient, and accurate technology for microplastic research. Its high throughput and broad polymer coverage make it a valuable tool in environmental science, public health studies, and regulatory compliance frameworks. Continued methodological refinement and standardization will further enhance its utility in assessing microplastic pollution and guiding mitigation strategies.

Reference

• Cizdziel, J., 2020. Microplastics in the Mississippi River and Mississippi Sound. Mississippi Water Resources Research Institute.
• Scircle, A., Cizdziel, J.V., Tisinger, L., Anumol, T., Robey, D., 2020. Occurrence of Microplastic Pollution at Oyster Reefs... Toxics.
• Cheng, M.L.H., et al., 2021. A baseline for microplastic particle occurrence and distribution in Great Bay Estuary. Marine Pollution Bulletin.
• Bringer, A., Le Floch, S., Kerstan, A., Thomas, H., 2021. Coastal ecosystem inventory with characterization and identification of plastic contamination. Marine Pollution Bulletin.
• Hildebrandt, L., El Gareb, F., Zimmermann, T., et al., 2022. Spatial distribution of microplastics in the tropical Indian Ocean. Environmental Pollution.
• Ourgaud, M., et al., 2022. Identification and Quantification of Microplastics in the Marine Environment Using LDIR. Environmental Science & Technology.
• Ng, E.L., et al., 2021. Microplastic pollution alters forest soil microbiome. Journal of Hazardous Materials.
• Bäuerlein, P.S., et al., 2022. Microplastic discharge from a wastewater treatment plant: LDIR vs. optical microscopy. Water Science and Technology.
• Whiting, Q.T., et al., 2022. High-throughput detection and characterization of microplastics using LDIR. Analytical and Bioanalytical Chemistry.
• Samandra, S., et al., 2022. Assessing exposure of the Australian population to microplastics through bottled water consumption. Science of The Total Environment.
• Liu, S., et al., 2023. Detection of various microplastics in placentas, meconium, infant feces, breastmilk and infant formula. Science of The Total Environment.