Thermal TDMS

The effectiveness of using SEE coupled to GC with a thermal desorption modulator (TDM) interface and TEA detection to analyse explosives has been evaluated by Francis et al. [33] in soil samples and standards. 

BTT and BTN, butane-1,2,4-triol-trinitrate DNT, dinitrotoluene EGDN, ethylene glycol dinitrate HPLC, high-performance liquid chromatography LOD, limits of detection MDQ, minimum detectable quantities NB, nitrobenzene NG, nitroglycerine NN, nitronaphthalene NT, nitrotoluene PETN, pentaerythritol tetranitrate RDX, cyclotrimethylene trinitramine SFE, supercritical fluid extraction SGC, solvating gas chromatography TDM, thermal desorption modulator TNB, trinitrobenzene and TNT, trinitrotoluene. 

Figure 6.5 Thermal desorption mass spectra (TDMS) and thermogravimetry (TC) analysis for the mixtures of (a) Ca(NH2)2 and CaH2 (molar ratio 1 1), (b) CaNH and CaH2 and (c) Ca(NH2)2 and CaH2 (molar ratio 1 3)...

UPS Ultraviolet Photoelectron Spectroscopy XPS X-ray Photoelectron Spectroscopy AES Auger Electron Spectroscopy ESCA Electron Spectroscopy for Chemical Analysis TDMS Thermal Desorption Mass Spectroscopy LEED Low-Energy Electron Diffraction RHEED Reflection High-Energy Electron Diffraction EELS Electron Energy Loss Spectroscopy... 

The concept of thermal desorption modulation (TDM) finally found its own specific area of application as the essential interface device between the two columns of a comprehensive two-dimensional separation system [28]. The TDM device consisted of a short section of a column that could be rapidly and reproducibly heated by an electrical current passing through an electrically conductive film. The authors used a segment of a capillary column with a narrow film thickness, covered with a layer of electrically conductive paint as the modulating interface between the two columns (Figure 8). Substances retained on the stationary phase of this modulator section were pulsed into the second column by resistive heating. 

LMCS, longitudinally modulating cryogenic system. TDM, thermal desorption modulator. 

We do not feel this explanation of the peculiarities of polymerization to be sufficient since re-combination reactions in the presence of primary radicals, formed from the regulator molecules, takes place in thermal polymerization of styrene as well. However, in this case the change of polymerization rate with increase of n-lauryl mercaptan concentration wasn t noted (4). In connection with this, we feel it expedient to consider styrene polymerization as a simpler system in the presence of widely used peroxide initiators (e.g., benzoyl peroxide (BP), t-butyl perbenzoate (TBPB), and regulators - n-lauryl mercaptan (NLM), n-butyl mercaptan (TMB), t-octyl mercaptan (TOM), t-decyl mercaptan (TDM), t-dodecyl mercaptan CTDDM), and t-pentadecyl mercaptan (TPDM)). 

Awad et al. [56] reported on the thermal degradation of a series of alkylimidazolium molten salts. Elemental analysis, TGA, and thermal desorption mass spectroscopy (TDMS) were used to characterize the degradation process. A correlation was observed between the chain lengths of the alkyl groups and the thermo-oxidative stability as the chain length increased from propyl, butyl, decyl, hexadecyl, and octadecyl to eicosyl, the stability decreased. Analysis of the decomposition products by FTIR provided information about the decomposition products. It suggested that the thermal decomposition of imidazolium salts followed an SN2 process (Figure 3.12). 

Kinetics models of gas-solid non-catalytic reaction include uniform conversion model (UCN), multiple fine particle model (GPM), crack core model (CCM), phase-change model (PCM), change void model (CVM), thermal decomposition model (TDM), shrinking core model with multi-step reactions, and multi-step reaction model of formation porous structure in reaction etc. Among these models, the shrinking core model (SCM) is the most important and most widely used. For conversion of solid it is also the most simple and practical model. Commonly it is suitable for experimental data. However, it can only be used in some reactions of many solid reactions. A more complex model must be used in other cases. 

FIGURE 5.11 Thermal desorption mass spectroscopy (TDMS) profiles and hydrogen absorption curves. 

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