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Everaldo Silvino Dos Santos - One of the best experts on this subject based on the ideXlab platform.

  • modeling and simulation of breakthrough curves of recombinant 503 antigen using immobilized metal affinity expanded bed Adsorption Chromatography
    Separation and Purification Technology, 2016
    Co-Authors: Francisco Caninde De Sousa, Jackson Araújo De Oliveira, Carlos Eduardo De Araujo Padilha, Abimaelle Silva Chiberio, Daniella Regina Arantes Martins, Vitor Troccoli Ribeiro, Gorete Ribeiro De Macedo, Everaldo Silvino Dos Santos
    Abstract:

    Abstract In this study a mathematical model was used to simulate the breakthrough curves of the recombinant 503 antigen of Leishmania infantum chagasi using immobilized metal affinity expanded bed Adsorption Chromatography. Initially, experimental curves were carried out in different conditions such as superficial liquid velocity, settled bed height as well as the initial 503 antigen concentration. The particle swarm optimization (PSO) algorithm was used for global parameter estimation by a general rate model, which proved to be an efficient tool for parameter estimation in chromatographic processes. Modeling and simulation of the 503 antigen breakthrough curves displayed a good performance during the estimation and validation stages. The highest global process efficiencies obtained was 88.8%. Finally, the validated model was used in the optimization stage, showing the process and column efficiencies of 89.2% and 75.9%, respectively. The results showed the applicability of this approach for modeling and optimization of chromatographic processes.

  • recovery and purification of recombinant 503 antigen of leishmania infantum chagasi using expanded bed Adsorption Chromatography
    Journal of Chromatography B, 2015
    Co-Authors: Francisco Caninde De Sousa, Carlos Eduardo De Araujo Padilha, Abimaelle Silva Chiberio, Daniella Regina Arantes Martins, Gorete Ribeiro De Macedo, Everaldo Silvino Dos Santos
    Abstract:

    Abstract Visceral leishmaniasis, a disease caused by Leishmania infantum chagasi , represents a major public health problem in many areas of the world. However, there is currently no vaccine for human use. The aim of this work was to purify the 503 antigen of Leishmania i. chagasi directly from unclarified Escherichia coli feedstock through expanded bed Adsorption (EBA) Chromatography. Batch experiments were performed to optimize the Adsorption and elution conditions of the antigen onto a STREAMLINE™ Chelating resin using two central composite rotatable designs (CCRD). The results showed that the optimal binding conditions of the 503 antigen were pH 8.0 in the presence of 2.4 M NaCl. For the elution of the target protein, the optimized conditions included the presence of 600.0 mM imidazole. The Adsorption isothermal data of the 503 antigen were fitted to the Langmuir Adsorption isotherm. The EBA experiment successfully recovered 59.2% of the 503 antigen from the unclarified E. coli homogenate with a purification factor of 6.0.

Tianwei Tan - One of the best experts on this subject based on the ideXlab platform.

  • separation of capsaicin from capsaicinoids by macroporous resin Adsorption Chromatography
    IEEE Journal of Solid-state Circuits, 2015
    Co-Authors: Changxia Liu, Tianwei Tan, Ruican Liu, Peng Zhang, Yiming Chen, Fang Wang, Chunqiao Liu
    Abstract:

    The aim of present study is to develop an efficient and low-cost method for capsaicin production isolated from capsaicinoids by macroporous resin Adsorption Chromatography. HZ816 resin has shown the best Adsorption and desorption capacities for capsaicin among other resins. To optimize the operating parameters for separation, initial concentration, diameter-to-height ratio, mobile phase ratio, and crystallization method were investigated. When capsaicinoids solution (5 g/L) was loaded onto the column (diameter-to-height ratio = 1:12) with ethanol/1% w/w NaOH (4:6, v/v) as the mobile phase, capsaicin was purified most effectively. By using acid neutralization as the crystallization method, the purity of capsaicin improved from 90.3 to 99.5% with 82.3% yield. In conclusion, this study provides a simple and low-cost method for the industrial-scale production of high-purity capsaicin.

  • isolation of α arbutin from xanthomonas cgmcc 1243 fermentation broth by macroporous resin Adsorption Chromatography
    Journal of Chromatography B, 2013
    Co-Authors: Chunqiao Liu, Tianwei Tan, Peng Zhang, Fang Wang, Luo Liu, Li Deng
    Abstract:

    α-Arbutin is a glycosylated hydroquinone which has inhibitory function against tyrosinase. In this work, a one-step isolation of α-arbutin from Xanthomonas CGMCC 1243 fermentation broth by macroporous resin Adsorption Chromatography was investigated. The research results indicated that S-8 resin offered the best Adsorption and desorption capacities for α-arbutin than others and its equilibrium Adsorption data were well-fitted to the Freundlich isotherm. In order to optimize the operating parameters for separating α-arbutin, dynamic Adsorption and desorption tests on S-8 column Chromatography were carried out. Under optimized conditions (Adsorption volume of 7 bed volume (BV), mobile phase of 25% (v/v) ethanol solution and elution volume of 3 BV), the purity and recovery of α-arbutin were 97.3% (w/w) and 90.9% (w/w), respectively. The product was identified as α-arbutin by (13)C NMR and (1)H NMR analysis. Moreover, we scaled up S-8 column from laboratory test (10 cm × 2 cm ID) to large scale (500 cm × 100 cm ID) without diminishing α-arbutin yield. In conclusion, the results in this work provide a one-step and cost-effective method for large-scale production of α-arbutin.

  • One-step purification of epigallocatechin gallate from crude green tea extracts by mixed-mode Adsorption Chromatography on highly cross-linked agarose media.
    Journal of chromatography. A, 2007
    Co-Authors: Tianwei Tan
    Abstract:

    (-)-Epigallocatechin gallate (EGCG) was purified in one step from a green tea polyphenol (GTP) crude extract by Adsorption Chromatography on a Superose 12 HR 10/30 column. The mobile phase used was a mixture of acetonitrile and water with an optimum mobile phase compositions regarding purity, recovery and separation time of 78/22 (v/v). Maximum practical sample loading was 100 mg GTP per run (corresponding to 4.2 mg/ml Superose). An EGCG purity of 99% with recoveries in the range 60-65% was achieved in one step directly from the crude GTP extract. Full column regeneration was obtained using solvents in the following order: 0.5 M NaOH, distilled water and 30% acetic acid.

  • purification of the isoflavonoid puerarin by Adsorption Chromatography on cross linked 12 agarose
    Journal of Chromatography A, 2004
    Co-Authors: Tianwei Tan
    Abstract:

    The isoflavonoid puerarin in extracts of the well-known traditional Chinese drug Radix puerariae (root of the plant Pueraria lobata) can be separated from other isoflavonoids by Adsorption Chromatography on the cross-linked 12% agarose gel Superose 12 equilibrated in distilled water. The Adsorption is totally quenched by the addition of 50% acetic acid. The separation of the isoflavonoids is tentatively ascribed to interaction with the residues of the cross-linking reagents used in the manufacturing process of Superose 12. Thus, no useful separation can be achieved with non-cross-linked 12% agarose gel media. Symmetric elution profiles at high sample loadings (16 mg on a 24 ml column) suggest linear Adsorption isotherms for the isoflavonoids.

Bernd Trathnigg - One of the best experts on this subject based on the ideXlab platform.

  • liquid exclusion Adsorption Chromatography a new technique for isocratic separation of nonionic surfactants iv two dimensional separation of fatty alcohol ethoxylates with focusing of fractions
    Journal of Chromatography A, 2002
    Co-Authors: Bernd Trathnigg, Christina Rappel
    Abstract:

    Abstract Fatty alcohol ethoxylates can be analyzed using a combination of liquid Chromatography under critical conditions as the first dimension and liquid exclusion–Adsorption Chromatography as the second dimension. Transfer of fractions from the first to the second dimension is achieved using the full Adsorption–desorption (FAD) technique. The peaks of interest in the first dimension are trapped on a short precolumn before injecting them into the second dimension. Full Adsorption is achieved by increasing the water content in the mobile phase before the FAD column. When the fractions are desorbed by switching to the mobile phase of the second dimension, they are focused and reconcentrated. In this way, a full resolution of oligomers is achieved. As both dimensions are run in isocratic mode, density and refractive index detection can be applied, which allows an accurate quantitation.

  • liquid exclusion Adsorption Chromatography a new technique for isocratic separation of nonionic surfactants iii two dimensional separation of fatty alcohol ethoxylates
    Journal of Chromatography A, 2001
    Co-Authors: Bernd Trathnigg, Manfred Kollroser, Christina Rappel
    Abstract:

    Abstract A quantitatively accurate mapping of lower fatty alcohol ethoxylates can be achieved using a combination of liquid Chromatography under critical conditions as the first dimension and liquid exclusion–Adsorption Chromatography as the second dimension. With coupled density and refractive index detection in both dimensions, the contribution of preferential solvation can also be estimated. In most cases, however, the use of refractive index detection alone also yields satisfactory results.

  • reversed phase high performance liquid Chromatography of polyethers comparison with a theory for flexible chain macromolecules
    Journal of Chromatography A, 1998
    Co-Authors: A A Gorbunov, Alexander Skvortsov, Manfred Kollroser, Bernd Trathnigg, Michael Parth
    Abstract:

    Abstract Reversed-phase Adsorption Chromatography retention modes of polyethylene glycol (PEG), its mono and dimethyl ethers (MME and DME) and polypropylene glycol (PPG) are studied both experimentally and theoretically. The experimental conditions were: narrow- and wide-pore Spherisorb C18 adsorbents and two mixed-solvent systems (methanol–water and acetone–water) as mobile phases. At varying compositions of the mobile phase, fully-resolved chromatograms of polyether samples were obtained, in which all peaks could be identified, and the dependencies of the distribution coefficient on the degree of polymerization for PEG and PPG molecules were extracted by processing these chromatograms. The data were interpreted by using a theory of homopolymers based on a continuum Gaussian chain model of flexible macromolecules and a slit-like model of pores of the stationary phase. Two regimes of an Adsorption Chromatography of macromolecules are examined in relation to the well-known Martin rule, the role of pore size and the end-group effects being discussed. The theory proved to describe the experimental data on both polymers well, in the whole range of molecular masses studied, and thermodynamic parameters characterizing interactions of ethylene oxide and propylene oxide (PO) repeating units in polyether molecules with the adsorbent pore walls have been determined from a comparison of the theory with the experimental data. The conditions corresponding to the critical Chromatography mode are estimated from the thermodynamic data for PEG and methanol–water system as being at about 76% of methanol, while for the PPG and acetone–water system, it is shown that such critical conditions at the given temperature are not attainable. Additionally, the mean thickness H of adsorbed PEG and PPG macromolecules was estimated as being equal to about 3–10 A. The parameter H proved to be a decreasing function of the water content in the mixed solvent. The same estimate of thickness H≈2.6 A is obtained for both polymers in pure water.

  • theory of liquid Adsorption Chromatography of macromolecules applied to polyethylene glycol and fatty alcohol ethoxylates
    Journal of Chromatography A, 1997
    Co-Authors: Bernd Trathnigg, B Maier, Alexei Gorbunov, Alexander Skvortsov
    Abstract:

    Liquid Adsorption Chromatography retention modes of poly(ethylene glycol) (PEG), its mono- and dimethyl ethers (MMEs and DMEs) and also of fatty alcohol ethoxylates (FAEs) are studied both experimentally and theoretically. The experimental system under investigation was a Spherisorb S5W 80 A column and isopropanol–water as the mobile phase. At various compositions of the mobile phase (in the range of 75 to 87% of isopropanol) chromatograms exhibiting good peak resolution were obtained and the dependencies of the elution volume on the number of repeating EO units for both PEG and FAE samples evaluated on the basis of a closer inspection of the chromatographic data. The experiments did not reveal any differences between the chromatographic behavior of PEGs, MMEs and DMEs, while the FAEs gave substantially smaller values of elution volume at all mobile phase compositions. These data were interpreted by using a molecular-statistic theory of homopolymers (to describe both PEG, MME and DME) and two-block copolymers (for FAEs) based on a continuum Gaussian chain model of macromolecules and a slit-like model of pores of stationary phase, wide pore approximation and the Adsorption Chromatography mode for PEG molecules were assumed in the development of this theory. This theory described very well the experimental data obtained, and two thermodynamic parameters characterizing interactions of EO units of PEG and both EO and (CH2)n chains of FAE molecules with the adsorbent pore walls have been determined from the comparison of the theory and the experiments. Although the mean thickness of adsorbed oxyethylene chain, H, was estimated as being equal to about 3.5–4.5 A, H proved to be slightly decreasing with increasing isopropanol content in mobile phase. Chromatograms visualizing the Adsorption of PEG and FAE molecules are presented, and the correspondence between the theoretical approach and the experimental situation under investigation is discussed.

Ping Hu - One of the best experts on this subject based on the ideXlab platform.

  • tartaric acid induced conversion of protopanaxadiol to ginsenosides rg3 and rg5 and their in situ recoveries by integrated expanded bed Adsorption Chromatography
    IEEE Journal of Solid-state Circuits, 2016
    Co-Authors: Dan Huang, Yuerong Wang, Hongyang Zhang, Yang Li, Min Zhang, Shengli Ruan, Ping Hu
    Abstract:

    : Panax ginseng has been applied in traditional Chinese medicine for over 2000 years. It is still one of the most popular herbs in recent decades. The prescribed ginseng-containing medicines consist of protopanaxadiol and protopanaxatriol ginsenosides, which are the major constituents of the herb. Minor ginsenosides at low levels in the herb, such as Rg3 and Rg5 , have attracted more rising attention than the major ones. The existing approaches to prepare Rg3 and Rg5 usually rely on either steamed red ginseng as the source or chemical/enzymatic conversion of protopanaxadiol to the targets. It is still highly desirable to effectively achieve such minor components. In this paper, a method integrated extraction of protopanaxadiol and conversion of it to Rg3 and Rg5 has been proposed. Protopanaxadiol was extracted and simultaneously converted to Rg3 and Rg5 by d,l-tartaric acid. The targets were absorbed by resins on expanded bed Adsorption Chromatography and were then separated from other ginsenosides in different stages. Compared with conventional methods, the developed process has advantages in shortening time consumption and improving the conversion ratio of protopanaxadiol, which is promising in directly achieving Rg3 and Rg5 from P. ginseng.

  • combination of integrated expanded bed Adsorption Chromatography and countercurrent Chromatography for the direct extraction and purification of pseudohypericin and hypericin from st john s wort hypericum perforatum l
    IEEE Journal of Solid-state Circuits, 2015
    Co-Authors: Yang Li, Yuerong Wang, Hongyang Zhang, Ping Hu, Min Zhang
    Abstract:

    St. John's wort has attracted particular attention because of its beneficial effects as an antidepressant, antiviral, and anticancer agent. A method for the combination of integrated expanded bed Adsorption Chromatography and countercurrent Chromatography for the simultaneous extraction and purification of pseudohypericin and hypericin from the herb is presented in this paper. Firstly, the constituents were extracted and directly adsorbed by expanded bed Adsorption Chromatography under optimal conditions. The stepwise elution was then performed by expanded bed Adsorption Chromatography that enriched the targets with higher purities and recoveries compared to other methods. Secondly, the eluent fractions from expanded bed Adsorption Chromatography were further separated by two-step high-speed countercurrent Chromatography. A two-step high-speed countercurrent Chromatography method with a biphasic solvent system composed of n-hexane/ethyl acetate/methanol/water with a volume ratio of 1:2:1:2 was performed by stepwise changing the flow rate of the mobile phase. Consequently, 5.6 mg of pseudohypericin and 2.2 mg of hypericin with purities of 95.5 and 95.0%, respectively, were successfully obtained from 40 mg of crude sample.

  • development of a method to extract and purify target compounds from medicinal plants in a single step online hyphenation of expanded bed Adsorption Chromatography and countercurrent Chromatography
    Analytical Chemistry, 2014
    Co-Authors: Yang Li, Yuerong Wang, Hongyang Zhang, Min Zhang, Nan Wang, Ping Hu
    Abstract:

    Pure compounds extracted and purified from natural sources are crucial to lead discovery and drug screening. This study presents a novel two-dimensional hyphenation of expanded bed Adsorption Chromatography (EBAC) and high-speed countercurrent Chromatography (HSCCC) for extraction and purification of target compounds from medicinal plants in a single step. The EBAC and HSCCC were hyphenated via a six-port injection valve as an interface. Fractionation of ingredients of Salvia miltiorrhiza and Rhizoma coptidis was performed on the hyphenated system to verify its efficacy. Two compounds were harvested from Salvia miltiorrhiza, one was 52.9 mg of salvianolic acid B with an over 95% purity and the other was 2.1 mg of rosmarinic acid with a 74% purity. Another two components were purified from Rhizoma coptidis, one was 4.6 mg of coptisine with a 98% purity and one was 4.1 mg of berberine with a 82% purity. The processing time was nearly 50% that of the multistep method. The results indicate that the present me...

Janchrister Janson - One of the best experts on this subject based on the ideXlab platform.