Investigating the Use of the Agilent 8700 LDIR Chemical Imaging System in Published Literature

Significance of the topic

The Agilent 8700 Laser Direct Infrared (LDIR) chemical imaging system combines quantum cascade laser (QCL) mid‑IR illumination with rapid scanning optics and dedicated software to deliver fast, spatially resolved chemical maps. This capability addresses persistent bottlenecks in vibrational chemical imaging—long acquisition times, heavy data loads, and limited throughput—making high‑resolution infrared imaging more practical for routine quality control, material characterization, and research workflows across pharmaceuticals, food analysis, biomaterials, and geosciences.

Aims and study overview

This white paper surveys published research employing the Agilent 8700 LDIR and Agilent Clarity software over recent years. The objective is to summarize how different research groups have applied LDIR imaging to specific scientific problems, to highlight method capabilities and limitations, and to extract practical lessons for analytical laboratories considering LDIR adoption.

Methodology and instrumentation

The core analytical approach of the 8700 LDIR is mid‑IR reflectance imaging of targeted spectral bands using a broadly tunable QCL source. Key operational modes are Scan (fixed wavenumber imaging while optics raster) for fast particle/feature localization and Sweep (QCL frequency sweep at a fixed point) for full spectral acquisition and compound identification. The instrument covers ca. 1800–975 cm−1 (mid‑IR fingerprint region) and uses a thermoelectrically cooled single‑point MCT detector with rapid scanning optics to achieve high spatial resolution and throughput. Typical experimental choices reported in the literature include pixel sizes from 1 to 40 µm and spectral resolutions tuned to application needs. Agilent Clarity software is used for method creation, automated workflows, single‑ or multi‑peak ratio classification, library matching, and result reporting.

Instrumentation used

• Agilent 8700 LDIR chemical imaging system with proprietary QCL light source and rapid‑scan optics.
• Thermoelectrically cooled single‑point mercury‑cadmium‑telluride (MCT) detector.
• Imaging modes: visible wide field, visible high magnification, IR direct reflectance, IR attenuated total reflectance (ATR).
• Agilent Clarity software for automated image acquisition, spectral library management, peak/baseline selection, and classification.
• Common sample accessories: low‑e (Kevley) slides, gold‑ or aluminum‑coated filter membranes, microtome blades, sample planar tools, glue/adhesive supplies and slide holders.

Main results and discussion

• Advanced biomaterials: LDIR (reflection mode focused on the amide I region) confirmed secondary structure within peptide nanofibrils, distinguishing antiparallel β‑sheet signatures and explaining morphological differences between peptide sequences used for spiral nanostructure templating.
• Geoscience: Hyperspectral LDIR imaging of polished hand samples provided rapid mineral phase mapping. Spectral matching against the USGS library (cosine similarity) and PCA‑based segmentation revealed grain boundaries and mineral domains on samples up to ~27 × 72 mm with minimal sample prep compared to thin sectioning.
• Cellular agriculture: LDIR enabled rapid particle counts of edible porous microcarrier powder, providing reproducible particle density metrics essential for consistent cell seeding in scale‑up workflows (~2,000 microcarriers per mg reported for specific preparations).
• Pharmaceutical applications: Multiple groups compared LDIR against Raman, NIR and SEM‑EDX. LDIR produced comparable spatial distribution maps of APIs/excipients while reducing acquisition time dramatically (examples: ~7.5 minutes LDIR vs ~4 hours Raman; reports of up to ~30–100× faster acquisition). LDIR sometimes detected more small API domains and reported smaller Feret diameters than Raman. Method development focused on optimal wavenumber (peak/baseline) selection and pixel size tuning (≤10 µm often optimal for particle detection).
• Tissue analysis: In implant/explant studies, LDIR localized extracellular matrix proteins (e.g., collagen I) and mapped polymer components in multilayer stent explants without labeling or extensive sample processing, supporting in situ assessment of tissue integration.
• Food adulteration screening: LDIR screening methods (peak ratios and simple multi‑wavenumber classifiers) detected economically motivated adulteration in powdered food matrices rapidly—scan times on the order of minutes. Sensitivity varied by blending method and matrix (dry blending: ~82% sensitivity at 1% adulterant, 92–100% at ≥5%; wet blending was more challenging due to homogeneous dispersion).

Benefits and practical applications of the method

• High throughput: orders‑of‑magnitude faster mapping enables routine analysis of many samples or whole tablets/areas that would be impractical with point‑scan techniques.
• Non‑destructive, label‑free mapping: useful for materials where preservation or in situ analysis is required (e.g., implants, mineral hand samples).
• Flexible workflows: Scan versus Sweep modes allow rapid screening followed by targeted spectral confirmation.
• Accessible method creation: Clarity software automates peak/baseline selection and supports user libraries for rapid deployment without extensive chemometrics in many screening contexts.
• Broad application space: demonstrated utility in pharmaceutical QC and formulation development, food authenticity screening, biomaterial characterization, geoscience mineral mapping, and particle quantification for cellular agriculture.

Future trends and potential uses

• Integration with machine learning and chemometrics for automated classification, anomaly detection, and improved sensitivity to low‑level components.
• Expansion of curated, community spectral libraries (including matrix‑specific references) to improve identification confidence across domains.
• Development of standardized validation protocols for regulated environments (pharmaceutical QC, food safety) addressing quantitation, detection limits, and inter‑instrument reproducibility.
• Hybrid, multimodal workflows combining LDIR with Raman, SEM‑EDX or optical microscopy to leverage complementary chemical and elemental contrast where needed.
• Adaptation for at‑line / in‑process monitoring and higher throughput sample handling accessories to support industrial QC applications.
• Broader spectral coverage or tandem QCL modules to extend utility beyond the 1800–975 cm−1 window for certain analytes.

Conclusion

The Agilent 8700 LDIR system has been shown in peer‑reviewed studies to provide rapid, spatially resolved mid‑IR chemical imaging across diverse scientific and industrial contexts. Its principal strengths are speed, practical workflows for screening plus targeted spectral confirmation, and the ability to generate high‑definition distribution maps without complex sample preparation. Limitations reported include challenges detecting homogeneously dispersed or highly diluted adulterants in some matrices and the need for careful method optimization (wavenumber selection and pixel size). Overall, LDIR represents a compelling, high‑throughput complement or alternative to established vibrational imaging modalities for many real‑world analytical tasks.

References

1. Gowen AA, O'Donnell CP, Cullen PJ, Bell SEJ. Recent Applications of Chemical Imaging to Pharmaceutical Process Monitoring and Quality Control. European Journal of Pharmaceutics and Biopharmaceutics. 2008;69(1):10–22.
2. Alvarez‑Fernandez A, Pawar N, Sanchez‑Puga P, Zaccai NR, Maestro A. Peptide‑Guided Self‑Assembly: Fabrication of Tailored Spiral‑like Nanostructures for Precise Inorganic Templating. Advanced Functional Materials. 2024;35(1):2411061.
3. Gordon N, Beaudoin H, Kelso PR, Southwell B, Wright DD. Laser Direct Infrared Spectroscopy Hyperspectral Imaging; Applications in Geochemical Phase Mapping and Interpretation of Multidimensional Analysis. AGU/ESS Open Archive. 2024.
4. Zhou X, Zheng H, Wu Y, et al. Scalable Production of Muscle and Adipose Cell‑Laden Microtissues Using Edible Macroporous Microcarriers for 3D Printing of Cultured Fish Fillets. Nature Communications. 2025;16:1740.
5. Sacré P‑Y, Alaoui Mansouri M, De Bleye C, Coïc L, Hubert Ph, Ziemons E. Evaluation of Distributional Homogeneity of Pharmaceutical Formulation Using Laser Direct Infrared Imaging. International Journal of Pharmaceutics. 2022;612:121373.
6. Carruthers H, Clark D, Clarke FC, Faulds K, Graham D. Evaluation of Laser Direct Infrared Imaging for Rapid Analysis of Pharmaceutical Tablets. Analytical Methods. 2022;14(19):1862–1871.
7. Zaker Y, Yilmaz H, Lex TR, Guo C, Rodriguez JD, Willett DR. Advancing Pharmaceutical Tablet Analysis with Laser Direct Infrared (LDIR) Imaging. Journal of Pharmaceutical and Biomedical Analysis. 2025;262:116897.
8. Ojha AK, Rajasekaran R, Hansda AK, et al. Biodegradable Multi‑Layered Silk Fibroin‑PCL Stent for the Management of Cervical Atresia: In Vitro Cytocompatibility and Extracellular Matrix Remodeling In Vivo. ACS Applied Materials & Interfaces. 2023;15(33):39099–39116.
9. da Costa Filho PA, Cobuccio L, Mainali D, Rault M, Cavin C. Rapid Analysis of Food Raw Materials Adulteration Using Laser Direct Infrared Spectroscopy and Imaging. Food Control. 2020;113:107114.
10. Yeh K, Kenkel S, Liu J‑N, Bhargava R. Fast Infrared Chemical Imaging with a Quantum Cascade Laser. Analytical Chemistry. 2014;87(1):485–493.
11. Hildebrandt L, Zimmermann T, Sobakpo M, Hahn K, Profrock D. A Validated, Cost‑Effective Alternative: Gold‑Coated vs Aluminum‑Coated Membranes for LDIR Microplastic Analysis. 2025.