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1.
Eliana M. Alhadeff Andrea M. Salgado Nei Pereira Jr. Belkis Valdman 《Applied biochemistry and biotechnology》2004,113(1-3):125-136
An automated flow injection analysis (FIA) system for quantifying ethanol was developed using alcohol oxidase, horseradish
peroxidase, 4-aminophenazone, and phenol. A colorimetric detection method was developed using two different methods of analysis,
with free and immobilized enzymes. The system with free enzymes permitted analysis of standard ethanol solution in a range
of 0.05–1.0 g of ethanol/L without external dilution, a sampling frequency of 15 analyses/h, and relative SD of 3.5%. A new
system was designed consisting of a microreactor with a 0.91-mL internal volume filled with alcohol oxidase immobilized on
glass beads and an addition of free peroxidase, adapted in an FIA line, for continued reuse. This integrated biosensor-FIA
system is being used for quality control of biofuels, gasohol, and hydrated ethanol. The FIA system integrated with the microreactor
showed a calibration curve in the range of 0.05–1.5 g of ethanol/L, and good results were obtained compared with the ethanol
content measured by high-performance liquid chromatography and gas chromatography standard methods. 相似文献
2.
Graciela Díaz de Delgado Ramírez V. Belkis Miguel Delgado José Rosquete P. Carmelo 《Journal of chemical crystallography》1995,25(7):371-374
The title compound, formula C15H20O2, is orthorhombic, P212121 witha=8.747(2),b=12.025(3),c=12.554(3)Å,Z=4, andD
m
=1.32(2)g/ml. The structural analysis shows that the compound corresponds to eudesma-4(15),7(11)-dien-8,12-olide, a sesquiterpene lactone previously isolated fromAster umbellatus but whose crystal structure was unknown. 相似文献
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A. Sezai
Sara Gürsel Snmez Belkis Ustamehmetolu Mamed I. Mustafaev 《Journal of polymer science. Part A, Polymer chemistry》1997,35(7):1255-1263
A new class of water-soluble polypyrroles (PPy) has been developed. This was accomplished by oxidative matrix polymerization of pyrrole (Py) monomer with Ce(IV) in the presence of poly(acrylic acid) (PAA), poly(vinyl pyrrolidone) (PVP), and copolymers (CP) of vinyl pyrrolidone(VP) with acrylic acid (AA) [VP/AA; 25/75 (CP1), 50/50 (CP2), 75/25 (CP3)]. The soluble and insoluble interpolymer complexes were observed according to the nature (and conformation) of polymers in mixture, the ratio of components, and the pH of solutions. The role of PAA, PVP, CP, Py, and Ce(IV) concentrations, the order of component addition, and the pH of the solutions were investigated. The evidence and structural reasons for the formation of soluble interpolymer complexes of PPy with different polymers are discussed. It is proposed that the compactization of the polymer matrix as well as the disturbance of the regularity of reactive groups on the polymer chain decreases the possibility of formation of soluble interpolymer complexes. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1255–1263, 1997 相似文献
5.
Poly(N-vinylcarbazole), poly(N-carbazole) and poly(N-ethylcarbazole) powders were chemically synthesized by the reaction of ceric ammonium nitrate (CAN) with N-vinylcarbazole carbazole and N-ethylcarbazole in acetonitrile. Products were characterized by elemental analysis, Fourier transform infrared spectroscopy, scanning electron microscopy and viscosity, X-ray fluorescence and four-probe conductivity measurement. It is found that when a suitable concentration of CAN is used in the polymerization process, the conductivity of chemically synthesized polymers can be improved further by controlling the CAN addition. © 1997 John Wiley & Sons, Ltd. 相似文献
6.
Belkis Ustamehmetolu 《先进技术聚合物》1999,10(3):164-168
The reduction of six spirocompounds in the absence and presence of polymethylmethacrylate (PMMA) matrix was investigated by in situ spectrochemical measurements. The effect of polymer concentration and chemical structure of spirocompounds on the electrochromism in solution was investigated and an advantage of the presence of the PMMA matrix for two spirooxazine compounds in the bleaching process was reported. The vertical ionization potentials obtained with semiempirical quantum mechanical calculations and those obtained from λmax of the sample solutions in PMMA proved to be consistent with oxidation potentials obtained from cyclic voltammetry experiments. This correlation can be explained by the stability of compounds in the PMMA matrix. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
7.
Roemeria refracta DC. (Papaveraceae) of Turkish origin yielded two novel epimeric N-oxides, (?)-(5R, 11S,14R)-reframidine N-oxide ( = (?)-(5R, 11S,14R)-11,12-dihydro-14-methyl-11,5-(iminomethano)-5H -cyclohepta[1, 2-f: 4, 5-f′]bis[1,3]benzodioxole 14-oxide; 1 ) and (?)-(5R, 11S, 14S)-reframidine N-oxide ( = (?)-(5R, 11S, 14S)-11, 12-dihydro-14-methyl-11, 5-(iminomethano)-5H-cyclohepta[1, 2-f:4, 5-f′]bis[1, 3]benzodioxole 14-oxide; 2 ). The isolated (?)-roelactamine ( = (?)-11, 12-dihydro-14-methyl-11, 5-(iminomethano)-5H-cyclohepta[1, 2-f:4, 5-f′]bis[1, 3]benzodioxol-15-one, 4 ) is the first natural isopavinoid incorporating a lactam group. The epimeric (?)-15-(2-oxopropyl)reframidines ( = (?)-1-[11, 12-dihydro-14-methyl-11, 5-(iminomethano)-5H-cyclohepta[1, 2-f:4, 5-f′]bis[1, 3]benzodioxol-15-y1]propan-2-ones; 5/6 ) and the epimeric (?)-ethyl (reframidin-15-yl)acetates ( = (?)-ethyl [11, 12-dihydro-14-methyl-11, 5-(iminomethano)-5H-cyclohepta[1, 2-f:4, 5-f′]bis[1, 3]benzodioxol-15-y1]acetates; 7/8 ) are probably artifacts. (±)-Coclaurine ( 9 ), (±)-N-methylcoclaurine ( 10 ), (?)-roemeridine ( 11 ), and N-feruloyltyramine ( 12 ) are also isolated from R. refracta together with the previously reported bases. Specific 13C-NMR assignments are reported for the first time for the isopavines. 相似文献
8.
H. Yasemin Yenilmez Belkıs Ustamehmetoğlu Esma Sezer Zehra Altuntaş Bayır 《Journal of Solid State Electrochemistry》2018,22(2):505-517
The syntheses of new cobalt and zinc phthalocyanine complexes containing carbazole (Cz) substituents at the peripheral positions are reported (CzCoPc and CzZnPc). The reaction of Cz with 4-iodophthalonitrile in the presence of a catalytic amount of copper(I) oxide and potassium carbonate led to the formation of 4-(9H-carbazol-9-yl) phthalonitrile. Furthermore, by heating the dinitrile and anhydrous metal salts (CoCl2, Zn(CH3COO)2) at 160 °C in n-hexanol in the presence of DBU, the phthalocyanines were obtained. They were characterised by 1H NMR, FT-IR, UV-Vis and MS spectroscopic data. Aggregation behaviours of Pcs were investigated in THF. Electrochemical redox behaviour of CzCoPc was investigated by cyclic voltammetry depending on the potential range, and the oxidation and reduction products were followed by UV-Visible absorption measurements. Polymerisation of CzCoPc was carried out by potentiodynamic methods on glassy carbon electrode, and the catalytic activity of resulting polymer (P[CzCoPc]) was tested comparatively with polycarbazole (PCz)-coated electrode for dopamine and better response was obtained for P[CzCoPc] modified electrode. 相似文献
9.
Alexander V. Briceño Graciela Díaz de Delgado Belkis V. Ramírez William O. Velásquez Alí B. Bahsas 《Journal of chemical crystallography》1999,29(7):785-791
[Ba(C5H5O4)2(OH2)] is monoclinic, C2/c, with a = 4.472(1), b = 13.312(3), c = 22.236(5) Å, = 92.90(1)°, Z = 4, and D
m = 2.06 g cm–3. The barium atom is 10-coordinate with Ba—O distances in the range 2.749(2)–2.989(2) Å. The material suffers a complex decomposition process upon heating at temperatures between 25 and 600°C in dynamic nitrogen and static air atmospheres. FT-IR and gas chromatography analyses indicate that water, CO, CO2, methane, ethane, ethylene, propane, propylene, and butane, are evolved during the heating process, leaving a residue of BaCO3. 1H-NMR spectra of a sample heated at 200°C, showed isomerization of barium itaconate to barium methylmaleate. 相似文献
10.
Tekant Gözler Belkis Gözler Amarendra Patra John E. Leet Alan J. Freyer Maurice Shamma 《Tetrahedron》1984,40(7):1145-1150
Konyanin (), obtained from (Rutaceae), is the first known 1,4-dihydroarylnaphthalene lignan in which the lactone carbonyl is bonded to C-3 rather than to C-2. Detailed NMR spectral data have been complied for the accompanying lignans (-)-kusunokinin () and diphyllin (). 相似文献