Instrumentation for TVA and EGA

Stanton Redcroft (now PL Thermal Sciences Ltd) was a pioneer in developing techniques that coupled a Stanton Redcroft 1000 C thermobalance thermogravimetric analyser with FT-IR spectroscopy (Digilab FTS40 FT-IR spectrometer with 3200 data system). 

For certain applications, compared to a MS combination, FT-IR instrumentation has the advantages that it is inherently more simple - no vacuum involved - and it is research-grade quality, whereas a MS is likely to be a basic quadrupole device. While the MS could be more sensitive and would possibly provide more information as an evolved gas analyser, it would also have a much greater need for maintenance than an FT-IR instrument. 

Perkin Elmer supply a system 2000 TGA-IR interface. This is a single supplier fully optimised system with a powerful range of advanced graphics and post-run processing software including the ability to produce stack plots showing small changes and trends 

PL Thermal Sciences produce the PL STA MS. In this instrument a PL-STA 1500 analyser capable of making TGA and DTA measurements is coupled with an MS, thereby augmenting weight loss and the differential temperature response data with quadrupole mass spectral data of the evolved gases such as oxygen, sulfur dioxide, and carbon dioxide. With a transfer time of evolved gases to the MS of about 100 ms, the MS-EGA is virtually simultaneous. 

The TG-MS mode. Gases evolved in TGA are directly introduced into the MS in real time. This mode allows the concentrations of the evolved gases to be plotted against the weight loss of sample under heating. 

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