Thermogravimetric analysis spectrometry

Thermogravimetric analysis has also been used in conjunction with other techniques, such as differential thermal analysis (DTA), gas chromatography, and mass spectrometry, for the study and characterisation of complex materials such as clays, soils and polymers.35... 

High performance liquid chromatography (HPLC) and with mass spectrometry (LC-MS) Plasma emission spectroscopy (PES) Scanning electron microscopy (SEM) with elemental X-ray analysis Thermogravimetric analysis (TGA)... 

Thermogravimetric methods such as pyrolysis gas chromatography-mass spectrometry have been used to characterize hydrocarbon sludges from polluted soils [10]. In combination with conventional extraction and supercritical fluid extraction followed by gas chromatography-mass spectrometry, over 100 constituents were identified in soil samples. Thermogravimetric analysis-mass spectrometric results distinguished between the release of a component by thermosorption and by pyrolysis. 

Major instrumentation involved with the generation of thermal property behavior of materials includes thermogravimetric analysis (TG, TGA), DSC, differential thermal analysis (DTA), torsional braid analysis (TBA), thermomechanical analysis (TMA), thermogravimetric-mass spectrometry (TG-MS) analysis, and pyrolysis gas chromatography (PGQ. Most of these analysis techniques measure the polymer response as a function of time, atmosphere, and temperature. 

Early devices fbr thermogravimetric analysis were limited in precision and convenience when compared with DTA or DSC equipment. Now devices for simultaneous DSC and TG are on the market which can operate at high temps in reactive atms permitting the simulation of high temp reactions on a micro scale. The use of TG for the study of reaction kinetics was described in Sect 5.3.3. An exptl study of the sublimation of ammonium perchlorate was published by Jacobs and Jones (Ref 25). Similar techniques should find application in the study of other propint systems. The product gases have been collected for further analysis using gas chromatography and mass spectrometry... 

The thermal characterisation of elastomers has recently been reviewed by Sircar [28] from which it appears that DSC followed by TG/DTG are the most popular thermal analysis techniques for elastomer applications. The TG/differential thermal gravimetry (DTG) method remains the method of choice for compositional analysis of uncured and cured elastomer compounds. Sircar s comprehensive review [28] was based on single thermal methods (TG, DSC, differential thermal analysis (DTA), thermomechanical analysis (TMA), DMA) and excluded combined (TG-DSC, TG-DTA) and simultaneous (TG-fourier transform infrared (TG-FTIR), TG-mass spectroscopy (TG-MS)) techniques. In this chapter the emphasis is on those multiple and hyphenated thermogravimetric analysis techniques which have had an impact on the characterisation of elastomers. The review is based mainly on Chemical Abstracts records corresponding to the keywords elastomers, thermogravimetry, differential scanning calorimetry, differential thermal analysis, infrared and mass spectrometry over the period 1979-1999. Table 1.1 contains the references to the various combined techniques. 

FIGURE 8.14 Thermogravimetric analysis of sodium alginate under helium atmosphere coupled with mass spectrometry analysis of the evolved gases. Heating rate 10°Cmin 1. (Adapted from Raymundo-Pinero, E., et al., Adv. Mater., 18, 1877, 2006.)... 

Thermogravimetric analysis was performed on a Stanton Redcroft thermobalance in a flowing oxygen atmosphere at a heating rate of 10°C/minute. Thermal desorption/mass spectrometry (TD/MS) was carried out using am Extranuclear quadrupole mass spectrometer. 4 ... 

The precursor and the calcined catalyst were characterized by various techniques such as nitrogen adsorption, mercury porosimetry, X-ray diffraction (XRD), atomic emission spectrometry by inductively coupled plasma (ICP), thermogravimetric analysis, and temperature-programmed reduction (TPR). More details about the catalyst preparation and characterization can be found in a previous work (22). 

Thermogravimetric analysis (tga) and thermal desorption/mass spectrometry (td/ms) were used as described previously [5]. Sample sizes were typically 10 mg, with heating rates of 10°C/min. 

Dyszel (1985) performed a thermogravimetric analysis/atmospheric-pressure chemical-ionization mass spectrometry (TGA/APCIMS) on green coffee beans. Using various combinations of 14 (M+1) ions, the author concluded that unknown coffees can be matched, with varying degrees of certainty, to known coffees for their country of origin. 

This was mentioned by Dyszel (1985) as found to be present in green coffee when trying to find a way for differentiating coffees of various origins. One of the ions (M+l) studied by thermogravimetric analysis/ atmospheric pressure chemical ionization mass spectrometry is 149 but the molecular weight of coumarin is 146. It is therefore difficult to determine where the error is. 

Dyszel S.M. (1985) Characterization of green coffee beans by combined thermogravimetric analysis/atmospheric pressure chemical ionization mass spectrometry. Thermochimica Acta 87, 89-98. 

The purity of the compounds was characterized by elemental analysis, molecular analysis ( H NMR, mass spectrometry), thermodifferential and thermogravimetric analysis and separative techniques such as HPLC, GC and capillary zone electrophoresis [127]. This procedure provided highly pure products for use in the interlaboratory studies, e.g. arsenobetaine was shown to be more than 99.8% pure. 

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