Mass spectrometry differential thermal analysis

Thermogravimetry - Differential Thermal Analysis - Mass 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... 

Thermal properties of several chlorinated phenols and derivatives were studied by differential thermal analysis and mass spectrometry and in bulk reactions. Conditions which might facilitate the formation of stable dioxins were emphasized. No two chlorinated phenols behaved alike. For a given compound the decomposition temperature and rate as well as the product distribution varied considerably with reaction conditions. The phenols themselves seem to pyro-lyze under equilibrium conditions slowly above 250°C. For their alkali salts the onset of decomposition is sharp and around 350°C. The reaction itself is exothermic. Preliminary results indicate that heavy ions such as cupric ion may decrease the decomposition temperature. 

DTA-MS Differential thermal analysis None Mass spectrometry... 

Leinweber P, Schulten HR. Differential thermal analysis, thermogravimetry and in-source pyrolysis-mass spectrometry studies on the formation of soil organic matter. Thermochim. Acta 1992 200 151-167. 

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. 

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. 

Abstract. Gas interstitial fullerenes was produced by precipitation of C6o from the solution in 1,2 dichlorobenzene saturated by O2, N2, or Ar. The structure and chemical composition of the fullerenes was characterized by X-ray powder diffraction analysis, FTIR spectroscopy, thermal desorption mass spectrometry, differential scanning calorimetric and chemical analysis. The images of fullerene microcrystals were analyzed by SEM equipped with energy dispersive X-ray spectroscopy (EDS) attachment. Thermal desorption mass spectroscopy and EDS analysis confirmed the presence of Ar, N and O in C60 specimens. From the diffraction data it has been shown that fullerite with face centered cubic lattice was formed as a result of precipitation. The lattice parameter a was found to enhance for precipitated fullerene microcrystals (a = 14.19 -14.25 A) in comparison with that for pure C60 (a = 14.15 A) due to the occupation of octahedral interstices by nitrogen, oxygen or argon molecules. The phase transition temperature and enthalpy of transition for the precipitated fullerene microcrystals decreased in comparison with pure Cgo- Low temperature wet procedure described in the paper opens a new possibility to incorporate chemically active molecules like oxygen to the fullerene microcrystals. 

The synthesis of the complex is followed by the most important step of characterization of the complex. The composition and the structural features of both the ligand and complex have to be established before embarking on further studies. There exist many methods by which the composition and structural features of the complexes are studied. Some of the methods are (i) elemental analysis, (ii) X-ray crystallography, (iii) UV-Vis absorption spectra, (iv) infrared spectroscopy, (v) Raman spectroscopy, (vi) thermal methods of analysis such as thermogravimetry, differential thermal analysis, (vii) nuclear magnetic resonance spectroscopy (proton, multinuclear), (viii) electrospray mass spectrometry. Depending upon the complexity of the system, some or all the methods are used in the studies of complexes. 

With the present arrangement, I can interchange the several furnace assemblies I use with the differential thermal analysis I can move a data acquisition system from apparatus to apparatus I can put reaction apparatus in position for direct monitoring by mass spectrometry and I can use the exhaust facilities effectively. In addition, I saved money which can be put to better use. 

During investigation of a new material it is unlikely that any single thermal analysis technique will provide all the information required to understand its behavior. Complementary information is usually needed, which may be from another simultaneous thermal technique such as thermogravimetric-differential scanning calorimetric-mass spectrometry (TG-DSC-MS), gas chromatography (TG-GC, or DSG-GG), or spectroscopic methods such as IR spectroscopy or X-ray photoelectron spectroscopy (XPS). 

Mara. Kamei and Osada [109 described a detailed study of the thermal decomposition of TNT. They examined the decomposition by differential thermal analysis, thermogravimetry, infra-red spectroscopy. HSR and mass spectrometry. One of their most important findings was that TNT produced free radicals already in the vicinity of the melting point, that is SO C. The substances which promote the decomposition of TNT are free radicals which are stable at room temperature. They are insoluble in benzene or chloroform and are partly oxidized polymeric substances. 

The method of analysis should be clearly stated and abbreviations such as MTA (mass-spectromelric thermal analysis) and MDTA (mass spectrometry and differential thermal analysis) avoided. 

Since all polymeric intermediates, and in many instances also the final ceramics, are amorphous, only thermal and spectroscopic methods can be utilized to characterize the thermal conversion. The most extensive studies have been performed on the polymer N-methylpolyborosileizane (PBS-Me), made from the single source precursor TADB. The pyrolysis has been monitored in situ by differential thermal analysis combined with thermo-gravimetric analysis and mass spectrometry (DTA/TG/MS). For ex situ investigations, batches of the polymer were treated at different temperatures, cooled to room temperature, and characterized by infrared spectroscopy and nuclear magnetic resonance spectroscopy. 

Applying conventional (thermogravimetry TG Differential thermal analysis DTA evolved gas detection EGD) and combined (thermogravimetry-mass spectrometry TG-MS) techniques, the pCD inclusion complexes with thymol and Lippia sidoides Cham EO (LsCEO) extract produced by kneading method were characterized. Its formations were detected through released gas... 

The first task of the specialist in environmental pollution studies is identification of the chemical substances that cause deleterious effects. This is followed by an effort to identify the pathways by which these substances have reached their locus of action, to find their sources, and finally to eliminate or minimize those sources. The tools for identification and measnrement of the amounts of such substances are those of analytical chemistry, namely, spectroscopy, mass spectrometry, gas and liquid chromatography, differential thermal analysis, and neutron activation analysis. These snbjects are discussed fully elsewhere in this encyclopedia. 

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