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1.
Solid state M-4-Me-BP compounds, where M stands for bivalent Mn, Fe, Co, Ni, Cu, Zn, Pb and 4-Me-BP is 4-methylbenzylidenepyruvate, have been synthesized. Simultaneous thermogravimetry-differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy, elemental analysis, and complexometry were used to characterise and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, thermal stability and thermal decomposition of the isolated complexes. 相似文献
2.
The Pt-Ir microelectrode modified through one step electropolymerization is proposed for the isocitrate amperometric biosensor construction. The enzyme (isocitrate dehydrogenase-ICDH), coenzyme (NADP(+)) and mediator (Meldola's Blue) were immobilized onto the microelectrode surface in one step from a PIPES buffer solution containing pyrrole. The optimized experimental conditions were 25 cycles of cyclic voltammetric in a solution containing 3.58 10(-5) mol l(-1) of mediator, 3.51 10(-4) mol l(-1) of coenzyme and 2.68 U ml(-1) of enzyme. In contrast to the biosensor for isocitrate reported in literature, just one enzyme was immobilized and no coenzyme addition in the solution of analysis was necessary. Catalytic currents were proportional to the isocitrate concentration between 7.7 10(-6) and 1.04 10(-4) mol l(-1), showing good repeatability. The detection limit of the proposed biosensor was 3.50 10(-6) mol l(-1), the response time was lower than 20 s, the lifetime was about 30 determinations and no significant interference of sugars and citric acid was verified. Orange juice samples were analysed by both methodology biosensor and spectrophotometric commercial kit, and the obtained results presented a good correlation. The data demonstrated that the developed biosensor is suitable for isocitrate determination in orange juice without matrix interferences. 相似文献
3.
Natalia Cambiaghi Atilio Fernando Luis Fertonani Elcio Cruz de Oliveira 《Molecules (Basel, Switzerland)》2022,27(22)
One of the quality control parameters of ethanol fuel is pH, established by the Brazilian standard ABNT NBR 10891, whose scope is specific for hydrated ethanol fuel, and by the American standard ASTM D 6423, which focuses on anhydrous ethanol fuel. This study presented a modified and optimized structure using a single solvent, both for the glass electrode and the external reference electrode, to minimize the presence of the liquid junction potential for measuring the pH of hydrated ethanol fuel. The Box–Behnken design enabled us to determine the optimal condition expected for the new measurement system, which was compared with the systems proposed by the standard references and the turning range of acid–base indicators using parametric and nonparametric tests. The results revealed that the pH values obtained by the different systems are statistically different, and that only the values obtained by this proposal are suitable for the pH range found by the indicators. The optimized electrode presented an adequate response sensitivity to the Nernst equation, having an operational behavior adequate for the modified and optimized glass electrode for pH measurements in hydrated ethanol fuel. 相似文献
4.
Guizellini Filipe Corrêa Franzin Bruno Trevizan da Silva Matheus Antonio Abra Luciana Mazotti Hojo Ossamu Pastre Iêda Aparecida Ribeiro Clóvis Augusto Paiva-Santos Carlos de Oliveira Fertonani Fernando Luis 《Journal of Thermal Analysis and Calorimetry》2021,143(1):47-60
Journal of Thermal Analysis and Calorimetry - The aim of this work is to synthesize and characterize a new structured silver–clay dried, calcined or sintered at different temperatures... 相似文献
5.
Gustavo Guadagnucci Fontanari José Manuel Martins Marcelo Kobelnik Iêda Aparecida Pastre José Alfredo Gomes Arêas José Paschoal Batistuti Fernando Luis Fertonani 《Journal of Thermal Analysis and Calorimetry》2012,108(1):141-148
This study used TG, DSC, and SDS-PAGE techniques to study protein isolates (PIs) in the powder form obtained from lupin seeds
flour Lupinus albus. Different methods of preparing PIs were tested, resulting in final products that were different only in relation to the
yield and protein content. The results of the protein analysis by SDS-PAGE showed that the same protein fractions were present
in the lupin seeds and in the obtained PIs. This result shows that the process of extraction was not damaging to the composition
of the original protein. On the other hand, the results of the thermal analysis (DSC and TG–DTG curves) obtained for the different
PIs, led to the detection of changes in the protein conformation through the ΔH values, which in general decreased with increasing values of pH and ionic strength in the experimental conditions of extraction. 相似文献
6.
G. G. Fontanari G. R. Souza J. P. Batistuti V. A. Neves I. A. Pastre F. L. Fertonani 《Journal of Thermal Analysis and Calorimetry》2008,93(2):397-402
Glutelin, the major protein fraction from guava seed, was obtained by fractioning as described by Osborne. The total proteins
were extracted and the isolates obtained by isoelectric precipitation presented similar DSC curves, concordant with the results
obtained by gel filtration chromatography and electrophoresis in polyacrylamide gel (PAGE-SDS). However, the DSC curves showed
a higher enthalpy with regard to the denaturing protein isolate (PI) extracted at pH 10.0 when compared to a PI at pH 11.5.
Such results are in accordance with those obtained for PI extracted at pH 10.0 using chromatography, this one being present
in the form of molecular aggregates of greater molecular mass. The glutelin fraction, however, did not present a denaturation
peak in the DSC curve, showing that the process for obtaining the same significantly altered its conformation. 相似文献
7.
Fertonani F. L. Milaré E. Benedetti A. V. Ionashiro M. 《Journal of Thermal Analysis and Calorimetry》2002,67(2):403-410
Thermogravimetry, cyclic voltammetry and other analytical techniques were used to study the reactions of mercury with pure
iridium. The results allowed to suggest when subjected to heat or anodic stripping voltammetry an electrodeposited mercury
film reacts with Ir substrate and at least three mass loss steps and three peaks appear in the mercury desorption process.
The first two were attributed to Hg(0)species removal like a mercury bulk and a mercury monolayer. The last can be ascribed
to the mercury removal from a solid solution with iridium.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
Thermal behaviour of intercalated 8-hydroxyquinoline (oxine) in montmorillonite clay 总被引:1,自引:0,他引:1
I. A Pastre I. do Nascimento Oliveira A. B. S Moitinho G. R. de Souza E. Y. Ionashiro F. L. Fertonani 《Journal of Thermal Analysis and Calorimetry》2004,75(2):661-669
The composite montmorillonite-8-hydroxyquinoline (Swy-1-8-HQ) was prepared by two different processes and studied by using
thermogravimetric analysis (TG/DTG and DSC), as well as helpful techniques as fluorescence in the UV-visible region and X-ray
diffraction. The composites developed fluorescent appearance, however with quantum poor efficiency and they exhibited distinct
TG and DSC thermal behavior. The fluorescence data of spectra associated to the TG/DT curves allowed to suggest that the 8-HQ
was present in the composites in two different circumstances: 1 - intercalated in the interlayer spaces (Swy-1-8-HQ2), rigidly
associated to the substrate feasible as a monolayer with the aromatic rings parallel to the silica layer; and/or, 2 - adsorbed
on the surface (Swy-1-8-HQ1), either as a bilayer formation or tilting of the molecules to the silicate layer sheet. All results
confirmed above are in agreement with X-ray diffraction patterns, once the interlayer space increases when 8-HQ is incorporated.
The experimental results confirm the formation of the composites in agreement with the method used in the preparation.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
E. Milaré F. L. Fertonani A. V. Benedetti M. Ionashiro 《Journal of Thermal Analysis and Calorimetry》2000,59(3):617-624
Thermogravimetry (TG) and other analysis techniques (EDX, SEM, Mapping surface, X-ray diffraction, inductively coupled argon
plasma emission spectroscopy and atomic spectrometry with cold vapor generation) were used to study the reaction of Hg with
Rh. The results permitted the suggestion that, when subjected to heat, an electrodeposited Hg film reacts with Rh to form
intermetallic products with different stabilities, as indicated by at least three mass loss steps. In the first step, between
room temperature and 160°C, only the bulk Hg is removed. From this temperature up to about 175°C, the mass loss can be attributed
to the desorption of a film of metallic Hg. The last step, from 175 to 240°C, can be ascribed to the removal of Hg from a
thin dark film of RhHg2 .
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.