Thermo Scientific TGA-IR Module for Nicolet FT-IR spectrometers

Significance of the topic

The coupling of Thermal Gravimetric Analysis (TGA) with Fourier Transform Infrared (FT‑IR) spectroscopy produces complementary data that goes beyond simple mass‑loss profiles by identifying the gases evolved during thermal events. This combined approach is essential in polymer deformulation, failure investigation, odor and out‑gassing identification, and in quality control of materials where knowledge of decomposition pathways and volatile species is critical.

Objectives and overview

This document presents the Thermo Scientific TGA‑IR Module designed for integration with Nicolet FT‑IR spectrometers and the OMNIC Mercury TGA software. The primary goals are to enable routine and research‑level evolved gas analysis, to simplify interpretation of TGA data via real‑time IR reconstructions, and to provide a compact hardware solution that preserves the integrity of evolved species from furnace to detector.

Methodology and analytical approach

The TGA‑IR workflow couples a TGA instrument (providing time/temperature resolved mass loss) with an FT‑IR spectrometer (providing molecular identification of gases). Key analytical elements are:

• Real‑time total infrared response (Gram‑Schmidt reconstruction) to flag gas evolution events.
• Processed IR spectra for identification of functional groups and specific volatiles.
• Windowed reconstructions (Chemigrams) to isolate spectral regions and follow targeted functional groups over time.
• Software algorithms (OMNIC Mercury) that accelerate automated identification and correlate IR signals with TGA mass‑loss profiles for easier deformulation and failure analysis.

Used Instrumentation

The TGA‑IR Module and its key specifications are summarized below:

• Compatibility: Designed to install in the sample compartment of Nicolet 380, 6700/8700, iS10 or iS50 FT‑IR spectrometers or the Auxiliary Experiment Module; compatible with most TGAs that have an evolved gas option (check vendor compatibility).
• Gas cell: Nickel‑plated aluminum flow cell, 10 cm pathlength, total volume ~22 mL (optimized for purge flows 35–100 mL/min); choice of KBr or ZnSe windows (KBr provides highest throughput and spectral range).
• Transfer line: Glass‑lined stainless steel transfer line to connect directly to a TGA furnace tube; designed to eliminate cold spots and minimize condensation; available lengths: 5 ft (152 cm) standard or optional 8 ft (244 cm); tubing 1/8" O.D. with compression fittings.
• Temperature control: Integrated digital controllers for cell and transfer line with setpoints from ambient to 300 °C to prevent condensation of evolved species.
• Detectors: Recommended DTGS detector for general TGA‑IR (spectral range ~7800–350 cm⁻¹, good sensitivity and linearity for quantitation); optional MCT detector available for higher speed and sensitivity when required.
• Physical/power: Module dimensions ~255 × 391 × 237 mm, module weight ~6.0 kg; power 120 V/3 A/60 Hz or 240 V/1.5 A/50 Hz (module and transfer line only).

Main results and discussion

While the document is a product specification rather than a research report, it highlights how combined TGA‑IR data enables deeper interpretation of thermal events. Representative outputs include:

• Gram‑Schmidt reconstructions that indicate when gases evolve during decomposition.
• Time‑resolved profiles showing which species are released at specific temperatures or times, enabling correlation with mass‑loss steps.
• Automated Mercury TGA analysis that proposes compound identifications from the IR reconstructions, simplifying deformulation workflows.

These capabilities allow analysts to move from observing mass changes to assigning chemical identities to the released volatiles, improving diagnosis of material composition, processing differences, and failure origins.

Benefits and practical applications

The integrated TGA‑IR solution offers several practical advantages:

• Direct identification of evolved gases—facilitates deformulation, determination of stabilizer loss, plasticizer evaporation, or decomposition products.
• Improved failure analysis—assists in pinpointing chemical origins of degradation, contamination, or manufacturing variability.
• Odor/out‑gassing investigations—enables correlation of specific volatiles with sensory or performance issues.
• Flexible sample coverage—applicable to rubbers, polymers, resins, adhesives, packaging, pharmaceuticals, wood, and soils.
• Routine and research use—OMNIC software provides both real‑time monitoring and post‑run automated interpretation to support workflows across QA/QC and research labs.

Future trends and opportunities

Potential developments and extensions that would enhance evolved gas analysis include:

• Higher sensitivity detectors and faster data acquisition (e.g., wider use of cooled MCTs) to resolve transient release events and trace volatiles.
• Hybrid coupling with mass spectrometry (TGA‑IR‑MS) for orthogonal confirmation and improved structural elucidation of complex mixtures.
• Advanced chemometrics and machine‑learning algorithms to deconvolute overlapping spectra, automate component identification, and predict decomposition pathways.
• Improved transfer‑line materials and heated interfaces to extend analysis to higher temperatures and to reduce adsorption losses of reactive species.
• Miniaturized or modular flow cells for low‑volume samples and for integration into automated or high‑throughput platforms.

Conclusion

The Thermo Scientific TGA‑IR Module combined with OMNIC Mercury software provides a compact, robust solution for evolved gas analysis that integrates thermal and spectroscopic information. By enabling identification of decomposition gases in real time and by automating parts of the interpretive workflow, this system supports deformulation, failure analysis, and quality investigations across a broad range of materials.

References

Thermo Scientific. TGA‑IR Module Product Specifications. Thermo Fisher Scientific; 2014.