Simultaneous Thermal Analyzer with Evolved Gas Analysis

What is the Simultaneous Thermal Analyzer with Evolved Gas Analysis?

A simultaneous thermal analyzer with evolved gas analysis couples the instrument to an FTIR spectrometer or mass spectrometer so that each mass loss step and heat effect can be assigned to specific evolved species such as water, carbon dioxide or hydrocarbons.

Overview

A heated transfer line carries evolved gases from the furnace to an infrared gas cell or a mass spectrometer ion source, keeping the line at 180 to 250 degrees Celsius to prevent condensation. The coupling adds identification capability to the mass and thermal signals, so a weight loss can be attributed to a chemical process rather than merely quantified. Infrared identifies functional groups and common gases such as water, carbon dioxide, carbon monoxide, carbonyls and hydrocarbons, while mass spectrometry detects hydrogen, nitrogen and other infrared-inactive species and can follow isotope-labelled compounds. Dilution by the balance purge reduces sensitivity, so flows must be optimised and documented, and the time lag between the sample and the detector must be accounted for when aligning the signals. Typical configurations cover ambient to 1000 or 1500 degrees Celsius with balance resolution of 0.1 microgram.

How does it work?

The instrument combines a thermobalance with a heat-flow or differential thermal sensor on a single sample holder inside one furnace, so mass and thermal signals share exactly the same temperature, heating rate and atmosphere. Because there is no second sample, results cannot be offset by sample-to-sample variation in mass, particle size or packing, which is the main advantage over running a TGA and a DSC separately. The heat-flow signal can be calibrated with indium to give melting enthalpies and heat capacity, while the balance gives mass loss steps, derivative peaks and residue. Typical temperature ranges extend from ambient to 1500 or 1600 degrees Celsius, with balance resolution of 0.1 microgram and heating rates of 0.1 to 50 degrees Celsius per minute. Purge gas is switched between inert and oxidising conditions, and a reference crucible is placed on the sensor alongside the sample crucible.

What are the key features?

• Heated transfer line at 180–250 °C to the gas analyser
• FTIR identification of functional groups and common gases
• Mass spectrometer option for infrared-inactive and isotope-labelled species
• Time-alignment software correcting detector lag across signals
• Optimised purge and coupling flows for sensitivity
• Combined report linking mass steps, heat effects and species

What are the technical specifications?

A typical simultaneous thermal analyzer with evolved gas analysis configuration offers temperature range of Ambient–1500 °C, balance resolution of 0.1 µg, heat flow or DTA signal of Heat flow or DTA sensor, transfer line temperature of 180–250 °C, IR spectral range of 4000–600 cm⁻¹ and mass spectrometer range of 1–300 amu. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Simultaneous Thermal Analyzer with Evolved Gas Analysis is used in decomposition pathway identification, battery and electrolyte gas evolution, waste and biomass pyrolysis, polymer additive identification and pharmaceutical degradation studies. Across the wider Simultaneous Thermal Analyzers class, laboratories also deploy it for polymer composition and additive analysis, pharmaceutical hydrate and polymorph studies and ceramic and mineral reaction analysis.

Which standards and certifications apply?

Relevant standards and methods include ASTM E1131, ASTM E967, ASTM E794, ISO 11358-1, ISO 11357-1 and USP <891>. Certification candidates for this model are CE, IEC 61010-1 safety and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Prepare sample and reference crucibles in the same way, with similar mass and packing, because the heat-flow signal depends on the symmetry of the two positions. Keep the balance purge flow stable and high enough to protect the weighing mechanism from condensable products, and verify with a blank run whenever the gas or flow changes. Calibrate temperature with Curie-point or melting-point standards and heat flow with indium before a critical campaign, and record crucible type, gas, flow, heating rate and sample mass with each curve. Simultaneous instruments show artefacts when the two crucibles differ: a sloping or drifting heat-flow baseline usually means asymmetry, damaged crucibles or contaminated sensors. Coupled techniques add transfer line maintenance, and the interface temperature must always be above the dew point of the evolved gases.

How do I select the right Simultaneous Thermal Analyzer with Evolved Gas Analysis?

Choose evolved gas analysis when the identity of the released compounds is part of the question, such as decomposition pathway, additive identification or failure investigation. If quantification of mass loss and heat effects is sufficient, a standard simultaneous analyzer costs less. In an RFQ, specify the detector type, spectral or mass range, transfer line temperature and sensitivity requirements.

How does it compare with other Simultaneous Thermal Analyzers variants?

Choose between the TGA-DSC and TGA-DTA sensor types first. A heat-flow sensor calibrated with indium gives quantitative enthalpies and heat capacity and suits polymers, pharmaceuticals and organics; a DTA sensor is more robust at high temperature and suits ceramics, minerals and metals where peak temperatures are enough. Then set the temperature range, since inorganic materials may need 1500 or 1600 degrees Celsius while organics require sub-ambient cooling. Decide whether evolved gases must be identified, which determines whether an FTIR or mass spectrometer coupling is needed. Check balance resolution, whether the crucible arrangement allows gas to flow over the sample, the gas switching capability, the software for combined signal evaluation and the calibration standards provided. For quality control, an autosampler converts the instrument into an unattended routine analyzer.