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1.
This paper describes the use of a thin-layered dual-band electrochemical cell operating at flow conditions to determine dipyrone (sodium salt of 1-phenil-2,3-dimethyl-4-methylaminomethanesulfonate-5-pyrazolone) by reaction with electrogenerated iodine. The electrolytic cell consisted of two closely spaced gold electrodes, the upper stream electrode serving as the generator electrode and the downstream electrode working as the collector electrode. A linear dynamic range from 2 to 15 μmol l−1 dipyrone was obtained by using a sample volume of 100 μl, with a detection limit of 1.1 μmol l−1. Standard deviation (S.D.) of 3.4% for 20 repetitive injections of a 40 μmol l−1 dipyrone solution and sampling frequency of 90 h−1 were achieved. The results obtained with the thin-layered dual-band electrochemical cell for dipyrone determination in three different pharmaceutical samples compared well with those found by iodimetry with coulometrically generated iodine. 相似文献
2.
Mauricio Gomes Constantino Kleber Thiago de OliveiraAdilson Beatriz Gil Valdo José da Silva 《Tetrahedron letters》2003,44(13):2641-2643
A synthesis of a functionalized bicyclo[6.2.1]undecane, N-(7-hydroxymethyl-bicyclo[6.2.1]undeca-3,5,9-trien-2-yl)-4-methyl-benzenesulfonamide, is described. Starting with a [6+4] cycloaddition between cyclopentadiene and cycloheptatrienone, the final product was prepared in five steps with an overall 37% yield. The remarkable resistance to hydrolysis of an intermediate lactam was overcome by tosylating the amide and reducing with LiAlH4. 相似文献
3.
Sunny K. S. Freitas Felipe L. Oliveira Thiago C. dos Santos Danilo Hisse Claudia Merlini Célia M. Ronconi Prof. Dr. Pierre M. Esteves 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(7):2342-2347
A thermally stable carbocationic covalent organic network (CON), named RIO-70 was prepared from pararosaniline hydrochloride, an inexpensive dye, and triformylphloroglucinol in solvothermal conditions. This nanoporous organic material has shown a specific surface area of 990 m2 g−1 and pore size of 10.3 Å. The material has CO2 uptake of 2.14 mmol g−1 (0.5 bar), 2.7 mmol g−1 (1 bar), and 6.8 mmol g−1 (20 bar), the latter corresponding to 3 CO2 molecules adsorbed per pore per sheet. It is shown to be a semiconductor, with electrical conductivity (σ) of 3.17×10−7 S cm−1, which increases to 5.26×10−4 S cm−1 upon exposure to I2 vapor. DFT calculations using periodic conditions support the findings. 相似文献
4.
Carla Marisa Brito Carvalho Marta Akemi FujitaTimothy John Brocksom Kleber Thiago de Oliveira 《Tetrahedron》2013
New β-fused uracil-porphyrin conjugates were synthesized by the tetramerization of uracil-pyrroles under acidic conditions. Two different synthetic approaches were systematically studied in order to evaluate their efficiency, as well as the possibility to obtain a single regioisomer. Metallation effects were studied for aggregation in solution, and preliminary photophysical experiments were also performed in order to evaluate the potential of these new compounds. 相似文献
5.
Luiz Carlos Domingos Batista Thiago Izidoro Silva Santos José E. Lima Santos Djalma Ribeiro da Silva Carlos A. Martínez-Huitle 《Electroanalysis》2021,33(1):57-65
MOF-235 is presented as an orange powder, with crystals of the octahedral formation. It was already used as adsorbent to remove different compounds from water; however, no attempts have been published about the exploration of the MOF-235 application as electrochemical sensor for organic compounds yet. MOF-235 was synthetized and after that, it was characterized by SEM, XRD and FTIR. Graphite electrodes (GEs) were modified with different MOF-235 ratio (5 %, 7 %, 10 %, 12 % and 14 %) and these modified GEs were characterized by cyclic voltammetry (CV) measurements in order to determine the effect of MOF-235 concentration on the current response. Results indicated that, a significant improvement on the current response was attained at MOF-235(10 %)/GE respect to unmodified GE. This behavior is related to the pore structure and multiple active sites on the MOF surface. The performance of the MOF-235(10 %)/GE as electrochemical sensor for detecting catechol was assessed by differential pulse voltammetry (DPV). Catechol detection response of MOF-based sensor provided a detection limit of about 12.79 μmol L−1 with a correlation coefficient (R2) of about 0.9928 ranging from 12 to 514 μmol L−1. Finally, MOF-235(10 %)/GE was used to determine catechol in real water matrixes. 相似文献
6.
Adilson Beatriz Roberto da Silva Gomes Mauricio Gomes Constantino Gil Valdo José da Silva Kleber Thiago de Oliveira 《Tetrahedron letters》2014
A bicyclo[6.2.1]undecane model compound of the core structure of the biologically active furanoheliangolide sesquiterpene was synthesized. This new and short route was developed by using a solvent-free Diels–Alder reaction between cyclopentadiene and 3-nitro-2-cyclohexenone, followed by simple transformations. Theoretical calculations were performed in order to understand reactivity aspects of the cycloaddition. 相似文献
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8.
Ribeiro Sabrina Dias Meneguin Andria Bagliotti Barud Hernane da Silva Silva Jhonatan Miguel Oliveira Rafael L. Asuno Rosana Maria Nascimento de Tormin Thiago Faria Muoz Rodrigo Alejandro Abarza Filho Guimes Rodrigues Ribeiro Clovis Augusto 《Journal of Thermal Analysis and Calorimetry》2022,147(13):7265-7275
Journal of Thermal Analysis and Calorimetry - Cellophane film production generates cellulosic residues from scraps, edges, and low-quality films. In this work, cellophane was used as a raw material... 相似文献
9.
Assessment of pharmacokinetic interaction between piracetam and l‐carnitine in healthy subjects 下载免费PDF全文
Gustavo D. Mendes Gabriela Traldi Zaffalon Antonio Sérgio Silveira Juliana Cama Ramacciato Rogério Heládio Lopes Motta Thiago Gagliano‐Jucá Anibal Gil Lopes José Cássio de Almeida Magalhães Gilberto De Nucci 《Biomedical chromatography : BMC》2016,30(4):536-542
A rapid, sensitive and specific method for quantifying piracetam in human plasma using Piracetam d‐8 as the internal standard (IS) is described. The analyte and the IS were extracted from plasma by one‐step precipitation of protein using an acetonitrile (100%). The extracts were analyzed by high‐performance liquid chromatography coupled with electrospray tandem mass spectrometry (HPLC‐MS/MS). The method had a chromatographic run time of 3.8 min and a linear calibration curve over the range 0.5–50 µg/mL (r > 0.99). This LC‐MS‐MS procedure was used to assess the bioavailability of two piracetam formulations: piracetam + l‐carnitine (Piracar®; 270/330 mg tablet) and piracetam (Nootropil®; 800 mg tablet) in healthy volunteers of both sexes. The geometric means with corresponding 90% confidence interval (CI) for test/reference percentage ratios were 88.49% (90% CI = 81.19 – 96.46) for peak concentration/dose and 102.55% (90% CI = 100.62 – 104.51) for AUCinf/dose. The limit of quantitation of 0.5 µg/mL is well suited for pharmacokinetic studies in healthy volunteers. It was concluded that piracetam (Piracar®; 270/330 mg tablet) has a bioavailability equivalent to the piracetam (Nootropil®; 800 mg tablet) formulation with regard to both the rate and the extent of absorption. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
10.
Thiago Henrique Napoleão Teodomiro Gomes dos Santos-Filho Emmanuel Viana Pontual Rodrigo da Silva Ferreira Luana Cassandra Breitenbach Barroso Coelho Patrícia Maria Guedes Paiva 《Applied biochemistry and biotechnology》2013,171(3):744-755
This work reports the use of matrices containing Cratylia mollis lectins (Cramoll 1,2,3-Sepharose and Cramoll 3-Sepharose) for isolation of glycoproteins from fetal bovine serum, human colostrum, hen egg white, and human blood plasma. Cramoll 1,2,3-Sepharose was able to bind a glycoprotein from fetal bovine serum which showed the same fetuin electrophoretic profile. The data indicate that this protein adsorbed to the matrix by interaction with Cramoll 3. Cramoll 1,2,3-Sepharose was not efficient to retain glycoproteins from human colostrum or commercial ovalbumin. Cramoll 3-Sepharose bound ovalbumin, and the support retained protein from hen egg white. Protein peaks eluted from the column with 1.0 M NaCl or 0.3 M galactose showed apparent molecular mass of ovalbumin. Two main proteins from blood plasma with apparent molecular mass 67 (similar to albumin) and 50 kDa (similar to fetuin) adsorbed on Cramoll 3-Sepharose and were eluted with 1.0 M NaCl as a single peak. Elution of adsorbed plasma proteins with 0.3 M galactose was less selective than with 1.0 M NaCl as revealed by SDS-PAGE. In conclusion, the Cramoll 1,2,3-Sepharose and Cramoll 3-Sepharose matrices were useful to separate glycoproteins from complex protein mixtures, and the adsorption phenomena was a carbohydrate-dependent event. 相似文献