Measuring diffuse refl ectance of solid samples with the Agilent Cary 60 UV-Vis

Importance of the Topic

Measuring diffuse reflectance of solid samples is critical for applications where the sample cannot be altered or removed from its environment. Accurate in situ reflectance data supports color monitoring and surface characterization in fields such as manufacturing process control and heritage conservation.

Objectives and Study Overview

This application note evaluates the performance of the Agilent Cary 60 UV-Vis spectrophotometer equipped with a remote fiber optic Diffuse Reflectance Accessory (DRA). The goal is to demonstrate rapid, nondestructive reflectance measurements on intact solid samples using colored PTFE standards as test materials.

Methodology

Reflectance data were collected over a 360–830 nm spectral range using Cary WinUV software. A white PTFE standard provided a 100 percent reflectance baseline. Spectra for white, yellow, red, blue and green PTFE samples were recorded and baseline corrected. Ten replicate scans on the blue PTFE sample assessed measurement reproducibility.

Instrumentation Used

• Agilent Cary 60 UV-Vis spectrophotometer
• Remote Diffuse Reflectance Accessory with 0/30° sample geometry
• Fiber optic coupler (up to 1.5 meter length)
• Cary WinUV control and data analysis software

Key Results and Discussion

All PTFE color samples exhibited smooth, noise-free reflectance profiles, confirming high light throughput and photometric stability of the system. The reproducibility study on the blue PTFE sample yielded an average standard deviation of 0.053 percent reflectance, with a maximum of 0.213 and a minimum of 0.007 percent, illustrating excellent scan-to-scan consistency.

Benefits and Practical Applications

• Nondestructive, remote measurement of solid surfaces
• Integrated video camera for precise probe placement and contamination detection
• Applications in art restoration, conservation and industrial quality control in automotive, coatings and printing sectors

Conclusion

The Cary 60 UV-Vis spectrophotometer paired with the remote DRA offers a versatile solution for diffuse reflectance analysis of solids. Its fiber optic flexibility and video positioning capability deliver fast, accurate and noninvasive measurements in both laboratory and field environments.

Future Trends and Applications

Future developments may include expanded spectral coverage, automated positioning systems and integration with hyperspectral imaging. These enhancements could enable in-line process monitoring, portable diagnostic tools and detailed surface mapping across a range of industries.

References

• Leona M, Casadio F, Bacci M, Picollo M. Identification of the Pre Columbian pigment Maya Blue on works of art by noninvasive UV Vis and Raman spectroscopic techniques. Journal of the American Institute for Conservation. 2004;43(1):39-54.
• Drollette D. Spectrophotometer finds cure for Edo Blues. Photonics Spectra. 2005;39(2).