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1.
The chemical composition of 200 renal stones, collected from Taxila, Rawalpindi and Islamabad regions in Pakistan, was determined by thermogravimetric (TG) and differential thermal analysis (DTA) techniques. The thermal curves show weight losses at various temperatures indicating dehydration and decomposition phenomena of renal stones. Results were compared with qualitative data obtained by IR analysis which confirmed the chemical composition of various stones in the solid state. The thermal curves helped in the differentiation of various kinds of water held by stones and their chemical composition was obtained by weight loss during pyrolysis. It was found that 26.5% of the stones were pure whewellite, 3% weddellite, 13% uric acid anhydrous, 7.5% struvite, 2.5% ammonium acid urate, 0.5% cystine and 47% stones had mixed composition. In the mixed state the most frequent combinations were those of calcium oxalate with uric acid (14.5%) and with phosphates (27.5%).
Zusammenfassung Mittels TG und DTA wurde die chemische Zusammensetzung von 200 Nierensteinen untersucht, die in den Gebieten Taxila, Rawalpindi und Islamabad in Indien gesammelt wurden. Die Thermogramme zeigen Masseverluste bei verschiedenen Temperaturen, die auf Dehydratation und Zersetzung der Nierensteine hinweisen. Die Ergebnisse wurden mit den qualitativen Resultaten aus der IR-Analyse verglichen, welche die chemische Zusammensetzung der verschiedenen Steine im festen Zustand bekräftigte. Die Thermogramme halfen bei der Unterscheidung von verschieden gebundenem Wasser, ihre chemische Zusammensetzung wurde durch Gewichtsverlust bei der Pyrolyse bestimmt. Man fand, daß 26.5 % der Steine aus reinem Whewellit bestanden, 3 % aus Weddellit, 13 % aus anhydrierter Harnsäure, 7.5 % aus Struvit, 2.5 % aus Ammmoniumhydrogenurat, 0.5 % aus Cystin und 47 % der Steine hatten eine gemischte Zusammensetzung. Die häufigsten Kombinationen der Mischzusammensetzungen waren Calciumoxalat mit Harnsäure (14.5 %) und mit Phosphaten (27.5 %).相似文献
2.
以8-羟基喹啉为配体的金属配合物是一种性能优良的有机电致发光材料,其中有关8-羟基喹啉铝(Alq3)研究已有大量报道,8-羟基喹啉锌(Znq2)研究还有待发展。介绍了两种以Znq2为基体的新型有机电致发光材料Znq2(H2O)2和(Znq2)4的合成方法。用IR、XRD、TG、DTA和荧光测试方法进行表征与分析表明:Znq2(H2O)2和(Znq2)4的玻璃化温度(Tg)分别为104.2℃和204.9℃;在161℃下Znq2(H2O)2脱去水分子成为Znq2,在361℃高温下四聚体(Znq2)4裂解为单体Znq2;Znq2(H2O)2和(Znq2)4具有很好的发光性能,在光致发光谱中λmax分别是505,550nm。 相似文献
3.
The TG and DTA curves and diffractograms of powdered CeO2 samples irradiated with a CO2 laser beam with powers of 0.41–1.39 kW/cm2 are presented. The laser treatment induced structural changes and probably generation of a metastable phase. X-ray diffraction coupled with thermal analysis was used to establish the structural modifications in the irradiated samples after heating. 相似文献
4.
Polypropylenes of differing morphologies were examined by differential thermal analysis. The problems of reordering during
the programmed heating are discussed. Four potential procedures by which the reordering could be inhibited are considered,
and three of these are experimentally assessed. Their advantages and deficiencies are identified. Two pretreatments, an etching
and a crosslinking, are recognised as able to qualitatively characterise the initial morphology, with a preference for the
former. A test to identify the occurrence of reordering is identified.
In celebration of the 60th birthday of Dr. Andrew K. Galwey 相似文献
5.
Complexes of adenine, AdH, with cobalt, nickel and copper chlorides were prepared and their thermodynamic functions were determined.
The complexing processes are endothermic in nature. The thermal behaviour of complexes was followed up by using TG and DTA
analyses. The stoichiometry of thermal decomposition of the investigated complexes was suggested.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
6.
Kate B. Poiesz Carol L. Grundner Nancy L. Redman-Furey 《Journal of Thermal Analysis and Calorimetry》2006,85(1):79-86
Characterization of the solid-state form (hydrate
or polymorph) of a pharmaceutical active is a key scientific and regulatory
requirement during development of and prior to seeking approval for marketing
of the drug product. A variety of analytical methods are available to perform
this task. By nature of the fundamental information it provides, TG-DTA offers
advantages over other methods in regards to monitoring and quantitation of
hydration state changes. In a single experiment with only a few milligrams
of sample, TG-DTA perceives minor changes in phase, quantitates total water
content and percent conversion, and illustrates hydrate type. All of this
is accomplished without the necessity of generating time-consuming standard
curves representing the differing ratios of hydrated to anhydrous forms. This
study describes the use of TG-DTA to monitor and quantitate humidity induced
solid–solid phase conversion of nitrofurantoin and risedronate. Percent
conversion was qualitatively observed by both TG and DTA signals and quantitated
by the TG. 相似文献
7.
Luciani G. Costantini A. Branda F. Scardi P. Lanotte L. 《Journal of Thermal Analysis and Calorimetry》2003,72(1):105-111
A traditional TG apparatus was modified by placing two permanent magnets producing a controlled magnetic field (TG(M): Magneto
Thermogravimetry). This technique proved to be useful to study both structural relaxation and crystallisation of ferromagnetic
metallic glasses. Results obtained for the amorphous alloys Fe40Ni40P14B6 and Fe62.5Co6Ni7.5Zr6Nb2Cu1B15, are reported in this paper. Structural relaxation can be evaluated by measuring changes in Curie temperature induced by
thermal treatments. Crystallisation in TG(M) is detected through a change in the measured apparent mass (difference between
the sample mass and magnetic force driving it upward). These results were confirmed by DSC analysis. Whether the obtained
crystalline phase is ferromagnetic, it can be identified through its Curie temperature, measured by TG(M). In fact the value
of 770°C measured as Curie temperature of crystallised Fe62.5Co6Ni7.5Zr6Nb2Cu1B15led to conclude that the only ferromagnetic crystalline phase is a-Fe. These hypothesis was confirmed by XRD analysis, showing
that the first crystallisation yields to a-Fe nanocrystals.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
Kaloustian J Pauli A-M Lechene de la Porte P Lafont H Portugal H 《Journal of Thermal Analysis and Calorimetry》2003,71(2):341-351
Cholesterol constitutes the major component of most gallstones. It was identified and determined, in gallstones, issued from
eleven patients, by thermal analysis: differential scanning calorimetry (DSC), with the use of the melting temperature and
enthalpy, thermogravimetry (TG), with the mass loss of water. Anhydrous cholesterol (ChA) was characterized by two endothermic
peaks (polymorphic, melting) and cholesterol monohydrate (ChH) by two endothermic peaks (dehydration, melting), too. Cha needle
and Chh plate crystals were observed under polarizing light microscopy. The numerous stones obtained from nine patients were
cholesterol stones: the ChA was higher 45 and lower 96%. ChH was present in stones of three patients.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
9.
10.