Fast and Easy Measurement of Scattering Samples with the Agilent Cary 60 UV-Vis Spectrophotometer

Significance of the topic

The accurate measurement of scattering and diffuse samples by UV-Vis spectrophotometry is critical across materials science, quality control, and environmental analysis. Standard transmission measurements often underestimate scattered light, leading to erroneous absorbance or reflectance data. Integrating sphere–based diffuse reflectance accessories (DRAs) address these limitations by capturing all redirected light, enabling reliable characterization of powders, films, coatings, and turbid liquids.

Objectives and study overview

This article presents the integration of the Agilent Cary 60 UV-Vis spectrophotometer with an internal diffuse reflectance accessory. It demonstrates how the 50 mm integrating sphere accessory extends the instrument’s capabilities to measure total, diffuse, and specular reflectance and transmission, improving accuracy and expanding sample versatility.

Experimental methodology and instrumentation

The key components and configurations include:

• Agilent Cary 60 UV-Vis spectrophotometer with high-intensity focused beam
• Internal DRA with a 50 mm diameter PTFE-coated integrating sphere
• Sample holders: clamp holder for 5 mm solids, V-shaped filter holder, thin film holder, 10 mm cuvette holder, powder cell holder (0.2–2 mL), reflection port cover, and 0°/8° port reducers (6 mm apertures)
• Cary WinUV Color software for chromaticity and CIELAB calculations (optional)

Measurements follow standardized setups: diffuse and total transmission with the reflection port sealed, specular setups using 8° reducers, and reflectance modes with calibrated PTFE or mirror standards.

Main results and discussion

The integrating sphere accessory successfully captured diffuse and specular components across multiple sample types. Reflectance measurements of colored PTFE standards demonstrated reproducible diffuse profiles, while specular reflectance of a gold mirror validated mirror-like response with the 8° port. Transmission tests on frosted films and formazin turbidity standards (125–2000 NTU) confirmed full light collection and consistent transmission spectra, even for highly scattering samples. The use of port reducers minimized substitution errors and enabled precise inclusion or exclusion of specular light.

Benefits and practical applications of the method

Key advantages include enhanced accuracy for turbid and scattering materials, rapid accessory installation (<5 min), and versatility for solids, films, and liquids. Practical applications span:

• Solar materials: evaluating reflectance and absorption of PV coatings
• Color and appearance control: measuring color, gloss, and consistency in textiles, paints, inks, and pharmaceuticals
• Coatings quality: assessing protective or decorative finishes
• Environmental monitoring: turbidity and haze measurement in water and beverages
• Polymer and optical materials: characterizing scattering in films, filters, and composites

Future trends and potential applications

Future developments may include remote and external DRAs with larger spheres for UV-Vis-NIR coverage, integration with automation and robotics for high-throughput screening, and coupling with complementary techniques such as fluorescence and hyperspectral imaging. Advances in sphere coatings and port optics will further reduce measurement artifacts and expand analytical ranges.

Conclusion

The Agilent Cary 60 UV-Vis with internal DRA offers a fast, flexible, and accurate solution for measuring scattering and diffuse samples. By capturing both diffuse and specular components in reflectance and transmission modes, it addresses the challenges of conventional UV-Vis analysis, supporting a wide array of research, QA/QC, and industrial applications.