When running thermogravimetric tests in the high-temperature range, haven't you sometimes wished that, in addition to the mass change, you could achieve a quick, more exact mass-specific characterization of the decomposition gases of the material through on-line analysis?
Only NETZSCH-Gerätebau can fulfill this wish for you with a progressive coupling of thermal analysis and mass spectrometry.
The combination, which insiders call the Skimmer Coupling System, unites the simultaneous thermal analysis instruments (STA 409 and STA 429) with a furnace tailor-made for the particular application, a quadrupole mass spectrometer for detection and analysis of the reaction gases, and a two-stage pressure-reduction system, to make up an ideally-suited analysis system.
Full advantage can be taken of the high level of detection sensitivity of the QMS only if a truly representative sample of the test atmosphere is transferred to the gas analyzer. Here, it is imperative that separation and loss of gas through condensation be prevented.
NETZSCH-Gerätebau has developed the perfect coupling system, made up of two orifices in tandem, which are held at the same temperature as the sample: the first orifice serves as a divergent nozzle and creates a compression zone, into which the second orifice, the so-called Skimmer, extends and creates a parallel molecular beam, which is directed at the ion source of the QMS.
The short transfer path (only a few millimeters) of the gas particles through the two orifices, which are located directly above the sample, guarantees a short response time and thus a perfect temperature-time correlation. Holding the sample and orifice system at the same temperature eliminates the disadvantageous condensation (for non-permanent gases) which usually occurs with capillary coupling systems and which is more or less dependent on the mass number. The result is a considerable increase in sensitivity (depending on the mass number, the intensity of the measurement signal is increased by up to over one hundred times).
Pyrolysis of a polystyrene sample under an inert gas atmosphere
Here, clearly stepped fragment packages can be observed. The mass number 208 represents the double monomer fragment.
Quantification of MS signals is possible by PulseTA®. This technique is based on the injection of a specific amount of gas into the inert carrier gas stream and the monitoring of changes in mass and enthalpy, which result from the incremental reaction progress.
Different versions of the skimmer coupling system are available for different applications:
- Skimmer system of Al2O3 for use in oxidizing atmospheres to 1450°C
- Skimmer system of glassy carbon for use in inert gas atmospheres to 2000°C.
The skimmer coupling system is a tool with high sensitivity, effectiveness and quality for material and process development as well as energy and environmental research.
NETZSCH offers
precision thermal analysis instruments including advanced dilatometers (with
a new basic R&D/QC dilatometer),
classical DSC & TGA (with
a new economical DSC), high temperature DSC
to 1650°C for specific heat, very high temperature STA
(TGA-DSC/DTA) to 2400°C (featuring the new STA
409-PC Luxx®), thermal
/ evolved gas analysis with fully-integrated FTIR & MS, plus
high resolution TMA and DMA.
We also feature leading technology for thermal conductivity and diffusivity measurement
as well as refractories testing including HMOR, CIC, and RUL.
Full advantage can be taken of the high level of detection sensitivity of the QMS only if a truly representative sample of the test atmosphere is transferred to the gas analyzer. Here, it is imperative that separation and loss of gas through condensation be prevented.
