Quality Control with Infrared Spectroscopy

Significance of the Topic

Fourier Transform Infrared Spectroscopy (FTIR) has become an indispensable tool for rapid, non-destructive chemical analysis across industries such as plastics processing, pharmaceuticals, petrochemicals, automotive and electronics. By providing both qualitative and quantitative insights without sample preparation or consumables, FTIR improves throughput in incoming goods inspection, failure analysis, process control and quality assurance.

Objectives and Study Overview

This application note (AN M80) presents how the ALPHA II FTIR spectrometer with OPUS-TOUCH software and interchangeable modules can be deployed for routine quality control tasks. It illustrates workflows for identity verification of raw materials, polymer type differentiation and surface contamination analysis on metals.

Methodology and Instrumentation

Ultraviolet–visible thermal radiation excites molecular vibrations; the instrument measures wavelength-dependent absorption to generate substance-specific spectra. Key components:

• ALPHA II FTIR spectrometer with integrated touchscreen and temperature-stabilized detector
• CenterGlow™ IR source with electronic control
• Platinum ATR module (diamond crystal) and one-finger pressure stamp
• Front-Reflection Module for non-contact surface analysis
• OPUS-TOUCH software for guided measurement, library search, spectral comparison and quantification

Key Results and Discussion

• Incoming Goods Inspection: Xanthan gum samples were compared against reference spectra for verification and identification. OPUS-TOUCH confirmed composition within specification in seconds.
• Polymer Analysis: ATR spectra of unlabeled plastic pellets clearly distinguished HDPE, LDPE and various polyamides. Automated library search enabled rapid subtype identification and quantification of crystallinity and additives.
• Surface Contamination on Metals: Diffuse/specular reflection measurements detected trace silicon oil on a steel sheet. Spectral matching identified polymethylhydrosiloxane, guiding corrective cleaning procedures.

Benefits and Practical Applications

FTIR with ATR and reflection modules offers:

• Minimal sample preparation and zero consumables
• Rapid qualitative and quantitative results in seconds
• User-friendly touchscreen operation for untrained personnel
• Modular design to adapt to diverse sample types and analysis modes
• Automated library searches for reliable identification

Future Trends and Applications

Advances in miniaturized detectors, higher-throughput sampling accessories and AI-driven spectral interpretation will expand FTIR into inline process monitoring, microplastic detection in environmental samples, advanced polymer lifecycle analysis and remote field measurements. Integration with cloud-based spectral libraries will further accelerate decision-making in global supply chains.

Conclusion

The ALPHA II FTIR system with OPUS-TOUCH streamlines routine quality control by delivering fast, accurate material identification and quantification across a wide range of applications. Its intuitive interface and modular design empower laboratories to replace complex wet-chemical methods, reduce turnaround time and improve reliability.

Reference

Application Note AN M80, Quality Control with Infrared Spectroscopy, Bruker Optics GmbH, 2021.