Quality Control with Infrared Spectroscopy

Importance of the Topic

Fourier Transform Infrared Spectroscopy (FTIR) has become an indispensable tool in modern quality control and materials analysis due to its rapid, non-destructive nature, minimal sample preparation and broad applicability across industries.

Objectives and Study Overview

This application note demonstrates how the Bruker ALPHA II FTIR system, equipped with OPUS-TOUCH software and various sampling modules, addresses key challenges in incoming goods inspection, polymer identification and surface contamination analysis.

Methodology and Instrumentation Used

FTIR measurements rely on molecular vibrational absorption of infrared radiation to generate characteristic spectra. The ALPHA II platform features:

• CenterGlow(TM) electronically controlled IR source and temperature-stabilized detector
• Integrated touch panel for intuitive operation
• Modular design allowing rapid exchange of sampling modules such as Diamond ATR, Platinum ATR, front-reflection and diffuse reflectance units
• OPUS-TOUCH software for guided workflows, background correction, library search, spectral comparison and quantification

A typical measurement sequence involves acquiring a background spectrum, placing the sample on the ATR or reflection module, applying contact pressure, recording the sample spectrum and evaluating results via the embedded user interface.

Key Results and Discussion

• Incoming Goods Inspection: Xanthan powder was rapidly verified against reference spectra within seconds, confirming identity and purity for acceptance.
• Polymer Analysis: ATR spectra of unlabeled plastic pellets revealed clear differentiation among HDPE, LDPE and various polyamide subtypes, supported by extensive spectral libraries for automated identification.
• Surface Contamination Analysis: Front-reflection measurements on a metal sheet detected an invisible silicon oil film. Library matching identified polymethylhydrosiloxane as the contaminant, guiding cleaning procedures.

Benefits and Practical Applications

FTIR with the ALPHA II system provides:

• Rapid qualitative and quantitative results in seconds
• Non-destructive testing without consumables or extensive sample prep
• User-friendly touchscreen interface enabling operation by untrained personnel
• Versatility to handle solids, powders, liquids and surface analyses via interchangeable modules

Future Trends and Opportunities

Emerging directions include integration with artificial intelligence for spectral interpretation, real-time inline monitoring, expanded cloud-based spectral databases, advanced multi-module automation and remote-controlled analytical workflows to further enhance efficiency and data traceability.

Conclusion

The Bruker ALPHA II FTIR system with OPUS-TOUCH software offers a robust, efficient and accessible solution for quality control and materials testing across diverse applications, replacing traditional wet-chemical methods and enabling fast, reliable results.

References

• Bruker Optics. Application Note AN M80 Quality Control with Infrared Spectroscopy. BOPT-01, 2021.