A challenge for forensic examiners is the
ageing and characterisation of bone fragments or decomposed skeletal remains.
Due to the sensitivity of thermal methods to morphological states, thermal
analysis has been selected as a technique which could overcome the difficulties.
In this preliminary study, TG-MS was applied to the characterisation of bone
fragments derived from the compact bone of pig rib specimens. TG-MS curves
were collected by heating bone samples to 1000C in an argon atmosphere.
Under these conditions, both the organic and inorganic phases decomposed,
producing a variety of organic fragments and carbon dioxide. Pyrolysis of
the organic phase, which is composed predominantly of collagen, occurred resulting
in the observation of ion fragments up to 110 amu. Selected fragments were
monitored and their observation is discussed in terms of the decomposition
of both the collagen phase and the inorganic carbonated hydroxyapatite phase.
fragmented species without any ambiguity and the structural/phase changes if any occurring during the deamination event. A detailed investigation of this sort warrants the use of techniques like thermogravimetric-mass spectroscopy (TG-MS) and temperature
Four amino acids and four different hair samples were studied in order to get information about the decomposition of human
hair, using combined (TG-MS) and DSC techniques. The thermal stability of the investigated amino acid samples was different.
Since they contain identical functional groups (-NH2, -COOH) some common mass/charge units were identified. However, due to their different chemical composition remarkable differences
have also been obtained. The results of the investigation of the amino acids were helpful to study the thermal fragmentation
of the hair samples. In our experiments, the effect of the heating rates was also studied.
Thermogravimetry (TG), thermogravimetry coupled with mass spectroscopy (TG-MS) and thermogravimetry coupled with Fourier transform
infrared spectroscopy (TG-FTIR) were used to characterise the thermo-oxidative behaviour of two intumescent coating materials.
The temperature dependence, the corresponding volatile products and the amount of residue of the different processes were
determined. Using both TG-MS and TG-FTIR results in an unambiguous interpretation of the volatile products. Characteristics
such as the influence of endothermic reactions, the release of non-flammable gases, the dehydrogenation enhancing the char
formation and the stability of the cellular char were discussed in detail. It was demonstrated, that TG, TG-MS and TG-FTIR
are powerful methods to investigate mechanisms in intumescent coatings and that they are suitable methods in respect to quality
assurance and unambiguous identification of such materials.
Summary Thermoanalytical techniques (TG, DSC) are frequently used in the investigation of the thermal properties of cyclodextrins and their inclusion complexes. However, the above techniques do not provide information on the chemical composition of the evolved fragments upon the thermal decomposition. In this study &-, &- and &-cyclodextrins and 4 methylated and 3 ethylated &-CD derivatives were investigated with a TG-MS combined thermoanalytical technique in order to get information about their fragmentation behaviour. By comparison of the TG/DTA curves, a different thermal behaviour was found for each of the native and the chemically modified cyclodextrins. Except for the water loss profiles and the solid-solid phase transformations, the thermal behaviour of the (investigated) native CDs do not show remarkable differences. However, the chemical modification of the native &-CD resulting in a new compound may change the strength of interactions between host and guest causing differences in the thermal stabilities of the derivatives. The mass spectrometry results supported the observed thermal differences and showed significant alterations in the fragmentation of ethylated and methylated compounds. The investigated natural CDs possess a very similar fragmentation profile, due to the common &-D-glucopyranose building units. In the case of modified CDs characteristic signals of the substituents are present.
A TA Instruments Thermal Analysis System (TG) has been interfaced to the Hewlett Packard 5972 quadrupole mass spectrometer.
An OSS-2 variable outlet splitter was plumbed between the TG and the mass spectrometer. This interface allows continuous monitoring
of the ion intensities of mass peaksm/e=18 (water) andm/e=44 (carbon dioxide) used to elucidate the TG transitions attributable to residual moisture in freeze-dried biological products.
Moisture specifications must be met in order to insure product stability throughout the approved shelf life. TG/MS results
are discussed for BCG Vaccine, BCG Live (Intravesical) and U. S. Standard Antihemophilic Factor. Karl Fischer and TG/MS moisture
results are compared.
For the quantitative analyses of evolved CO2and H2O during the thermal decomposition of solids, calibration curves, i.e. the amounts of evolved gases vs. the corresponding
peak areas of mass chromatograms measured by TG-MS, were plotted as referenced by the reaction stoichiometry of the thermal
decomposition of sodium hydrogencarbonate NaHCO3. The accuracy and reliability of the quantitative analyses of the evolved CO2and H2O based on the calibration curves were evaluated by applying the calibration curves to the mass chromatograms for the thermal
decompositions of copper(II) and zinc carbonate hydroxides. It was indicated from the observed ratio of evolved CO2and H2O that the compositions of copper(II) and zinc carbonate hydroxides examined in this study correspond to mineral malachite,
Cu2CO3(OH)2, and hydrozincate, Zn5(CO3)2(OH)6, respectively. Reliability of the present analytical procedure was confirmed by the fairly good agreement of the mass fraction
of the evolved gases calculated from the analytical values with the total mass-loss during the thermal decompositions measured
Sewage sludge disposal is a difficult task owing to increasingly restrictive re-use policies. Its final destination will obviously
depend on its nature and composition but the generation of energy is a significant option. The thermochemical conversion requires
exhaustive gas emission controls. In this regard, this paper offers the results of the use of mass spectrometry together with
a thermogravimetric analysis system used to study the thermal conversion processes of two kinds of sewage sludge under different
atmospheres simulating pyrolysis, gasification and combustion. This TG-MS combination indicates that gasification is the best
process for one kind of sludge while a co-combustion process is more suitable for the other.
spectrometry (TG-MS) was used to study the effect of the inorganic salts (NH4)2SO4 and (NH4)2HPO4,
active substances of many commercial forest fire retardants, on the pyrolysis
of Pinus halepensis needles and their main
components (cellulose, lignin and extractives). These salts seemed to affect
the pyrolysis of cellulose by increasing significantly the char residue, decreasing
the pyrolysis temperature and changing the composition of the evolved gases,
that is, increasing levoglucosenone and decreasing oxygen containing volatile
seemed to have negligible effect on the pyrolysis of lignin, while (NH4)2HPO4 increased the char residue and decrease the relative contribution of guaiacols
in the evolved gases. No effects of the inorganic salts on the extractives
were observed. Finally, the inorganic salts seemed to affect the pyrolysis
of pine-needles, mainly the cellulose component, but the effects were not
as intense as in the pyrolysis of cellulose.
–mass spectrometry (TG–MS) analysis is a very usefully method to confirm the content and species of the gaseous products of thermal decomposition and to contribute to a better understanding of the mechanisms of flame retardant, which might facilitate the development