Search results for "SEPARATION"
showing 10 items of 865 documents
Ultra-short ion-exchange columns for fast charge variants analysis of therapeutic proteins
2021
Abstract The purpose of this work was to study the potential of recently developed ultra-short column hardware for ion exchange chromatography (IEX). Various prototype and commercial columns having lengths of 5, 10, 15, 20 and 50 mm and packed with non-porous 3 µm particles were systematically compared. Both pH and salt gradient modes of elution were evaluated. Similarly, what has been previously reported for reversed phase liquid chromatography (RPLC) mode, an “on-off” retention mechanism was observed in IEX for therapeutic proteins and their fragments (25–150 kDa range). Because of the non-porous nature of the IEX packing material, the column porosity was relatively low (e = 0.42) and the…
Zinc oxide nanorod based immunosensing platform for the determination of human leukemic cells.
2019
Zinc oxide (ZnO) based nanostructures owing unique physical properties – high photoluminescence, bio- compatibility and other characteristics, therefore, they attract attention as building blocks suitable for biosensor development. In this research as a target we have used human leukemic cell line IM9 (IM9). IM9 was derived from the patient with a multiple myeloma and expressed cluster of differentiation proteins СD19 on the surface of 85–95% here investigated cancer cells. As a control sample healthy human's peripheral blood mononuclear cells (PBMC) were used and the expression of CD19 protein was found only in 5–9% of these cells. Two types of antibodies labeled by f…
Flow-through pore characteristics of monolithic silicas and their impact on column performance in high-performance liquid chromatography
2008
Abstract In order to elucidate the role of the flow-through characteristics with regard to the column performance in high-performance liquid chromatography (HPLC) native and n -octadecyl bonded monolithic silica rods and columns, respectively of 100 mm length and 4.6 mm ID with mesopores in the range between 10 and 25 nm and macropores in the range between 0.7 and 6.0 μm were examined by mercury intrusion/extrusion, scanning electron microscopy, image analysis and permeability. The obtained data of the flow-through pore sizes and porosity values as well as surface-to-volume ratio of the stationary phase skeleton enabled to predict their influence to the chromatographic separation efficiency…
Spherical ordered mesoporous silicas and silica monoliths as stationary phases for liquid chromatography
2006
Ordered mesoporous silicas such as micelle-templated silicas (MTS) feature unique textural properties in addition to their high surface area (approximately 1000 m2/g): narrow mesopore size distributions and controlled pore connectivity. These characteristics are highly relevant to chromatographic applications for resistance to mass transfer, which has never been studied in chromatography because of the absence of model materials such as MTS. Their synthesis is based on unique self-assembly processes between surfactants and silica. In order to take advantage of the perfectly adjustable texture of MTS in chromatographic applications, their particle morphology has to be tailored at the microme…
Phase separation of polymer blends in solution: A case study
2016
Abstract The phase behavior and phase separation features of the quaternary system poly- l -lactide (PLLA)/poly-rac-lactide (PLA)/dioxane/water were investigated. Experiments were performed with fixed total polymer concentration of 6 wt%, by varying the PLLA/PLA weight ratio. Blend weight compositions examined were 100/0, 80/20, 50/50, 20/80 and 0/100, at fixed dioxane/water weight ratio (87/13). Cloud point measurements reported that the demixing temperatures of blends are close to PLLA in the same mixed solvent, in line with the calculated spinodals. As regards to foam preparation, above the PLA cloud point, morphology is similar to pure PLLA foams; conversely, below PLA cloud point, the …
Preparation of polymeric foams with a pore size gradient via Thermally Induced Phase Separation (TIPS)
2015
Abstract Foams with a pore size gradient are promising materials for tissue engineering applications where a complex architecture involving morphological variations in space must be mimicked, e.g. in bone tissue repair. In this paper, a technique to obtain a porous scaffold with a pore size gradient is presented. The preparation procedure is based on Thermally Induced Phase Separation (TIPS), by imposing a different thermal history on the two sides of a polymeric solution. In this way, a gradient in thermal history is produced, which will generate a pore size monotonously varying along scaffold thickness. By controlling some parameters easy to manipulate, such as demixing temperature and/or…
Simultaneous Determination of Thiamin and Riboflavin in Mushrooms by Liquid Chromatography
2001
A simple, fast, inexpensive, and reliable method useful for the simultaneous, routine determination of thiamin and riboflavin in mushrooms is examined. It uses the extraction procedure, with slight modifications, proposed by the AOAC for the extraction of thiamin and riboflavin, followed by a liquid chromatographic separation on a reversed-phase Spherisorb ODS column with methanol/water as mobile phase gradient. Fluorometric detection is used at the following excitation and emission wavelengths, respectively, 360 and 425 nm in the case of thiamin and 422 and 515 nm for riboflavin. The analytical parameters of linearity, the precision of the method (RSD = 2.45 and 2.51% for thiamin and ribof…
Influence of annealing conditions on the photoelectrocatalytic performance of WO3 nanostructures
2020
[EN] Nanostructured WO3 photoanodes have been synthesized by electrochemical anodization under controlled hydrodynamic conditions in acidic media in the presence of 0.05 M H2O2. Subsequently, samples have been subjected to a thermal treatment (annealing) at different temperatures (400 degrees C, 500 degrees C and 600 degrees C) and under different gaseous atmospheres (air, N-2, Ar). The influence of these annealing conditions on the morphology, crystallinity, photoelectrochemical behavior and dopant chemistry of the different photoanodes has been investigated through Electronic Microscopy, Raman Spectroscopy, Photoelectrochemical Impedance Spectroscopy and Mott-Schottky analysis. In general…
Metal-Organic Frameworks as Versatile Heterogeneous Solid Catalysts for Henry Reactions
2021
Metal–organic frameworks (MOFs) have become one of the versatile solid materials used for a wide range of applications, such as gas storage, gas separation, proton conductivity, sensors and catalysis. Among these fields, one of the more well-studied areas is the use of MOFs as heterogeneous catalysts for a broad range of organic reactions. In the present review, the employment of MOFs as solid catalysts for the Henry reaction is discussed, and the available literature data from the last decade are grouped. The review is organized with a brief introduction of the importance of Henry reactions and structural properties of MOFs that are suitable for catalysis. The second part of the review dis…
Economic analysis of the scale-up and implantation of a hollow fibre membrane contactor plant for nitrogen recovery in a full-scale wastewater treatm…
2021
[EN] Nitrogen recovery technologies such as the hollow fibre membrane contactor are now being developed. However, an economic analysis is needed prior to their full-scale application in wastewater treatment plants. The aim of this study was to analyse the economic and environmental aspects of scaling-up this method. To achieve it, a full-scale 40,000 m3·day¿1-wastewater treatment plant influent flow rate was simulated jointly with a membrane contactor plant to evaluate the minimum costs of optimum operating conditions of membrane contactors (pH, feed flow rate and membrane surface). The optimum conditions for treating 600 m3·day¿1 of reject water was found to be 10 pH, 0.08 m3·s¿1 feed flow…