Stationary Phases
Mostrando 1-12 de 289 artigos, teses e dissertações.
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1. Per-Aqueous Liquid Chromatography for the Separation of Polar Compounds Preparation and Characterization of Poly(ethylene oxide co dimethylsiloxane) Based Stationary Phase
Poly(ethylene oxide-co-dimethylsiloxane) was thermally immobilized on silica particles-Si(PEO)-to separate small polar compounds with water-rich mobile phases. Poly(ethylene oxide-co-dimethylsiloxane) content on Si(PEO) stationary phase was optimized using a central composite design. Infrared spectroscopy, scanning electron microscopy, and thermogravimetric
Journal of the Brazilian Chemical Society. Publicado em: 2022
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2. AVALIAÇÃO DE ADITIVOS DE FASE MÓVEL E TEMPERATURA NA VIDA ÚTIL DE COLUNAS PARA CROMATOGRAFIA LÍQUIDA DE ALTA EFICIÊNCIA
Buffered solutions, additives, and column temperature are widely used in high-performance liquid chromatography to promote adequate retention of compounds and to improve the chromatographic separation. However, these factors can dramatically reduce the column lifetime. In this work, the effect of column temperature, pH and the salt type and concentration in
Quím. Nova. Publicado em: 2020-03
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3. Determination of Enantioselectivities by Means of Chiral Stationary Phase HPLC in Order to Identify Effective Proline-Derived Organocatalysts
The pyrrolidine fragment is a privileged scaffold within chiral ligands employed in coordination complexes exhibiting catalytic activity in asymmetric reactions and, more recently, as enantioselective organocatalysts per se. Likewise, the employment of (S)-proline as starting material constitutes the most direct form to synthesize those chiral derivatives. A
J. Braz. Chem. Soc.. Publicado em: 2018-05
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4. Solid-phase extractions in flow analysis
ABSTRACT Coupling solid-phase extraction (SPE) to flow systems has promoted a synergistic development. Whereas SPE mechanization leads to improved precision and higher sample throughput, as well as diminishes systematic errors and contamination risks, analyte concentration and separation from the sample matrix provides a remarkable impact on detectability an
An. Acad. Bras. Ciênc.. Publicado em: 2018
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5. Evaluation of short-chain-length polyhydroxyalkanoate accumulation in Bacillus aryabhattai
Abstract This study was focused on the polyhydroxybutyrate (PHB) accumulation property of Bacillus aryabhattai isolated from environment. Twenty-four polyhydroxyalkanoate (PHA) producers were screened out from sixty-two environmental bacterial isolates based on Sudan Black B colony staining. Based on their PHA accumulation property, six promising isolates we
Braz. J. Microbiol.. Publicado em: 2017-07
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6. Concentration Profiles of Regulated and Unregulated Pollutants Emitted from the Combustion of Soybean Biodiesel and Diesel/Biodiesel Blend Originating of a Diesel Cycle Engine
This study evaluated the concentration profiles of regulated and unregulated pollutants emitted from a stationary diesel engine cycle, operating at the speed of 1800 rpm and 0% load, using biofuels and binary blends. The experimental test considered fuel burning time on three different periods and storage times. The operation of the engine when it is still c
J. Braz. Chem. Soc.. Publicado em: 2017-04
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7. Biofilm production and beta-lactamic resistance in Brazilian Staphylococcus aureus isolates from bovine mastitis
Abstract Staphylococcus spp. play an important role in the etiology of bovine mastitis. Staphylococcus aureus is considered the most relevant species due to the production of virulence factors such as slime, which is required for biofilm formation. This study aimed to evaluate biofilm production and its possible relation to beta-lactamic resistance in 20 S.
Braz. J. Microbiol.. Publicado em: 2017-03
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8. Development of Molecularly Imprinted Polymers for Solid Phase Extraction of Parabens in Plasma Samples and Analysis by UHPLC-MS/MS
Two molecularly imprinted polymers (MIPs) were synthesized, by sol-gel and radical polymerization procedures. These MIPs were evaluated as selective stationary phases for miniaturized solid phase extraction (MISPE) to determine parabens in plasma samples by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Selective cavitie
J. Braz. Chem. Soc.. Publicado em: 2017-02
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9. Validated high performance thin layer chromatography method for the quantification of bioactive marker compounds in Draksharishta, an ayurvedic polyherbal formulation
ABSTRACT Draksharishta is an ayurvedic polyherbal formulation with Draksha (Vitis vinifera L., Vitaceae) as chief ingredient prescribed for digestive impairment, respiratory disorders and weakness. These herbal medicines containing biologically active compounds play a significant role. Therefore it is necessary to carry out the chemical standardization of bi
Rev. bras. farmacogn.. Publicado em: 2016-10
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10. Development of HPLC Analytical Techniques for Diterpene Glycosides from Stevia rebaudiana (Bertoni) Bertoni: Strategies to Scale-Up
Stevia rebaudiana is a plant well-known as a source of dozens of high potency non-caloric natural sweeteners, many of them still uncharacterized. Herein, we describe the development of several routine HPLC (high performance liquid chromatography) analytical techniques to better separate steviol glycosides. Different stationary phases/columns were used: rever
J. Braz. Chem. Soc.. Publicado em: 2016-08
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11. Self-Immobilization of Poly(methyltetradecylsiloxane) onto Metalized Silica Particles as Stationary Phases for HPLC
This work presents a study of the sorption of a pre-synthesized polysiloxane, poly(methyltetradecylsiloxane) - PMTDS, onto zirconized and titanized-silica particles that results in efficient stationary phases for reversed phase liquid chromatography. The sorbed materials, after 6 days at room temperature without any chemical or physical agent, denominated as
J. Braz. Chem. Soc.. Publicado em: 2016-06
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12. Influence of Alumina Phases on the Molybdenum Adsorption Capacity and Chemical Stability for 99Mo/99mTc Generators Columns
Technetium-99m is the clinically most used radionuclide worldwide. Although many techniques can be applied to separate 99Mo and 99mTc, the most commonly used method is the column chromatography with alumina as stationary phase. However, the alumina nowadays used has limited adsorption capacity of molybdate ions which implies the need to develop or improve ma
Mat. Res.. Publicado em: 31/05/2016