Rapid identification of o-rings, seals and gaskets using the handheld Agilent 4100 ExoScan FTIR

Importance of the Topic

In industrial and chemical plants, seals, gaskets and o-rings prevent leaks, ensure product integrity and protect personnel. Selecting the correct elastomeric material is essential to maintain safety, minimize downtime and reduce maintenance costs, especially when dealing with aggressive chemicals or extreme operating conditions.

Study Objectives and Overview

This application note demonstrates a rapid, non-destructive method for identifying carbon-black filled and non-filled sealing materials using a portable FTIR spectrometer. The study builds a spectral library for nine common elastomer types and validates the handheld Agilent 4100 ExoScan FTIR system’s ability to distinguish among them in real-world samples.

Methodology

• Fourteen samples representing nine sealing materials (fluorosilicone, silicone, Viton, EPR/EPDM, neoprene, butyl, Kalrez, NBR, polyurethane and natural rubber) were sourced from multiple manufacturers.
• Each sample was measured by lightly pressing the part against a spherical germanium ATR crystal.
• Spectra were acquired as a 20 s co-addition of interferograms at 8 cm⁻¹ resolution.
• Reference spectra were stored in the onboard MicroLab FTIR software library.
• A second batch of samples was measured days later to test the library match performance.

Instrumentation Used

• Agilent 4100 ExoScan handheld FTIR spectrometer
• Spherical germanium ATR interface for reduced penetration depth and minimal scattering by carbon black
• Agilent MicroLab FTIR software for real-time spectral acquisition, contact verification and library searching

Main Results and Discussion

• High-quality spectra were obtained for all materials, with clear fingerprint regions despite carbon-black fillers.
• First-hit library matches were correct for all 14 test samples.
• Five of the samples produced a close second match when filler levels were similar (e.g., silicone and fluorosilicone).
• Materials with differing filler content (e.g., NBR) did not cross-match closely, confirming the method’s sensitivity to formulation.

Benefits and Practical Applications

• Non-destructive testing preserves valuable parts and avoids sample preparation.
• Portable design enables in-situ verification at manufacturing lines or field locations.
• Rapid, real-time analysis reduces downtime and supports quality assurance.
• User-friendly software allows non-expert operators to obtain reliable results.

Future Trends and Opportunities

• Expanding the spectral library to include new polymer formulations and fillers.
• Integrating handheld FTIR data with plant maintenance management systems.
• Adapting the approach to other industrial materials, such as coatings or composites.
• Coupling with advanced chemometric tools and cloud-based libraries for remote support.

Conclusion

The Agilent 4100 ExoScan FTIR with germanium ATR provides a fast, accurate and portable solution for identifying elastomeric seals, gaskets and o-rings, including challenging carbon-black filled materials. Its non-destructive approach and onboard library enable reliable, on-site verification that supports safety, productivity and quality control.

Reference

Seelenbinder J. Rapid identification of o-rings, seals and gaskets using the handheld Agilent 4100 ExoScan FTIR. Agilent Technologies Application Note, November 2015.