ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
Language
Number of Hits per Page
Default Sort Criterion
Default Sort Ordering
Size of Search History
Default Email Address
Default Export Format
Default Export Encoding
Facet list arrangement
Maximum number of values per filter
Auto Completion
Topics (search only within journals and journal articles that belong to one or more of the selected topics)
Show more topics
Feed Format
Maximum Number of Items per Feed
Permalink If you want to be able to use settings permanently, you must save your settings and then set a Bookmark to the permalink
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    A closer study of chiral retention mechanisms (1998)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 10 (1998), S. 375-381 
    Details
    ISSN: 0899-0042
    Keywords: retention mechanisms ; separation of enantiomers ; chiral stationary phases ; equilibrium isotherms ; bonding ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The retention mechanisms and the separation of enantiomers on the classes of chiral stationary phases which are made by bonding isolated groups on the surface of an adsorbent are discussed. It is shown that retention on these phases originates from mixed mechanisms and how the individual contributions of these two mechanisms can be separated, by determining and modeling the equilibrium isotherms. A contribution originating from interactions of the isomers with the nonselective sites (type-I) and another one due to interactions with the enantioselective sites (type-II) can be determined and their importance studied as a function of several parameters, e.g., temperature or pH. This approach is illustrated with results obtained with different pairs of enantiomers on bovine serum albumin, 4-methylcellulose tribenzoate, or cellobiohydrolase immobilized on silica. Chirality 10:375-381, 1998. © 1998 Wiley-Liss, Inc.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    Estimation of the number of enantioselective sites of bovine serum albumin using frontal chromatography (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 5 (1993), S. 513-515 
    Details
    ISSN: 0899-0042
    Keywords: enantioselective retention ; albumin ; bilangmuir adsorption model ; frontal analysis ; saturation capacity ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On a column with bovine serum albumin (BSA) immobilized covalently to silica, the adsorption isotherms of the enantiomers of mandelic acid, tryptophan, 2-phenylbutyric acid, and N-benzoylalanine are measured using a buffered mobile phase. Knowing the amount of BSA immobilized on the column (36 mg), the ratio of the number of enantiomer molecules needed to saturate the enantioselective retention mechanism to the number of BSA molecules is determined. The mean of the set of eight enantiomers is 0.28. These data confirm that at most one enantioselective site exists for each BSA molecule for the kind of enantiomers studied. © 1993 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chir.530050707
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Theoretical study of recycling in preparative chromatography (1993)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 39 (1993), S. 809-819 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Using the equilibrium-dispersive model of chromatography, we have investigated recycling as a means to improve the recovery yields and possibly the production rates of chromatographic separations. When compared with the optimal values obtained for the conventional single-cycle regime, our results prove the potential for recycling in preparative chromatography. The analysis performed for the separation of two binary mixtures demonstrates that recycling not only improves the recovery yield but can increase the production rate under certain conditions. Different possibilities of collecting sufficiently separated fractions during recycling are compared. The mathematical model developed can be used effectively for designing optimal recycling strategies in preparative liquid chromatography.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690390509
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Optimizing experimental conditions for minimum production cost in preparative chromatography (1994)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 40 (1994), S. 594-605 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Optimum experimental conditions and column design parameters are calculated for most economical separation of binary mixtures by preparative liquid chromatography. The solvent consumption and capital costs are regarded as the two major cost contributions. Calculations were performed by using the numerical solution of the equilibrium-dispersive model of chromatography and a nonlinear simplex algorithm. Solvent consumption depends only on the column efficiency, the retention factor, and the loading factor. The production rate depends on the particle size, the column length, the mobile-phase flow velocity, the retention and the loading factors, and can be optimized with or without recovery yield constraints. A hybrid objective function was constructed to find the tradeoffs between the production rate and the solvent consumption.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690400404
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Measurement of transverse and axial apparent dispersion coefficients in packed beds (1996)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 42 (1996), S. 3041-3054 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The axial and transverse apparent dispersion coefficients of three solvents in two packed chromatographic columns were determined by pulsed-field-gradient nuclear-magnetic resonance in a range of mobile phase velocity. The column beds were packed with 5- μm particles of porous C18 silica or 30-μm particles of silica. The solvents used were methanol and acetonitrile (in an 80:20 ACN/water solution) in the former case and acetone in the latter. The coefficients were determined over a range of particle Peclet numbers from less than 0.1 to approximately 10 in the former case and 40 in the latter. The data obtained with short dispersion times were fitted to the correlations suggested by Giddings, Horvath and Lin, Huber, and Knox. These data agreed well only with the Giddings equation.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690421106
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Prediction of a protein band profile in preparative reversed-phase gradient elution chromatography (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 39 (1992), S. 877-885 
    Details
    ISSN: 0006-3592
    Keywords: adsorption ; chromatography ; gradient-elution ; isotherms ; proteins ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The overloaded band profiles of lysozyme in reversedphase preparative chromatography were recorded on a C18 chemically bonded silica column, with acetonitrile/water as the mobile phase. These experiments were carried out under isocratic conditions at 31.6, 31.9, and 32.2% acetonitrile (ACN) for loading factors up to 43% of the column saturation capacity and under linear-solvent-strength gradientelution with gradient slopes of 0.5 and 1% ACN/min, for loading factors up to 11.3%. The adsorption isotherms of lysozyme were measured for the same solvent compositions and found to be accurately accounted for by a bi-Langmuir isotherm model.With the use of a Craig model implementation of the equilibrium-dispersive model of chromatography, the band profiles of lysozyme were calculated. An excellent agreement was observed between these calculated profiles and the experimental profiles recorded at loading factors below 5%. By contrast, band profiles calculated using a Langmuir isotherm failed to describe the experimental bands. At column loadings exceeding 8%, a slight but systematic deviation takes place between calculated and experimental profiles. It is most probably explained by the considerable concentration effect of the gradient, making the band experience phase equilibrium in a concentration range that exceeds largely the one where the isotherm data have been measured.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260390810
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Radial distribution of the flow velocity, efficiency and concentration in a wide HPLC column (1997)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 43 (1997), S. 1964-1974 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The use of optical fibers in a fluorescence-detection scheme permits the accurate determination of the radial distribution of the transit time, the column efficiency, and the analyte concentration at the exit of a chromatographic axial-compression column (50 mmID). The results obtained demonstrate that the column is not homogeneous, but suggest a nearly cylindrical distribution of the packing density. The average velocity close to the column wall is 7% lower than along its axis and the HETP 25% higher. The lack of homogeneity of the column packing is another source of band broadening not taken into account in chromatography so far. It causes the apparent HETP derived from the conventional elution chromatogram recorded on the bulk eluent to be larger than the local HETP and the band profile to be unsymmetrical with a slight tail reminiscent of kinetic tailing.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690430806
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Optimizing the sample size and the retention parameters to achieve maximum production rates for enantiomers in chiral chromatography (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 40 (1992), S. 1210-1217 
    Details
    ISSN: 0006-3592
    Keywords: chiral separations ; optimization ; chromatography, preparative ; production rate ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The optimum experimental conditions (sample size and mobile phase composition) are calculated for maximum production rate of either one of two enantiomers contained in feeds of different compositions (1/1, 1/10, and 10/1). The products are obtained at 99% purity. The calculations use the equilibrium-dispersive model of chromatography and the equilibrium isotherms determined experimentally from the rear, diffuse boundary of overloaded elution profiles. The production rate measured experimentally under the optimum conditions calculated agree with 4% of the calculated values. There is an optimum value for the retention factor which is higher than predicted by a model assuming constant separation factor, because both separation factor and retention decrease with increasing organic solvent concentration in the mobile phase. © 1992 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260401011
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Production rate of an isotachic train in displacement chromatography (1995)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 41 (1995), S. 45-57 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The shock layer theory permits the derivation of an equation relating the thickness of the shock layer or mixed zone between successive bands in a fully developed isotachic train and the experimental parameters (mobile-phase flow velocity, concentration and retention factor of the displacer, column length, and average particle size of the packing material). It also permits the calculation of the amount of each product contained in this mixed zone. The main assumptions made are the use of the competitive Langmuir isotherm, the identity of axial dispersion coefficients, and the mass-transfer rate constants for different components. These equations make it possible to calculate the production rate and recovery yield achieved with an isotachic train, and to optimize the experimental conditions for maximum production rate. The shock layer thickness increases rapidly and the production rate decreases sharply when α-1 tends toward 0. In agreement with previous experimental results, there are well defined optimum flow velocity and displacer concentrations which vary depending on feed components. This theory permits an easy access to the optimization of these parameters.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690410106
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Effect of the flow rates in linear, ideal, simulated moving-bed chromatography (1997)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 43 (1997), S. 2960-2969 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The algebraic solution for linear, ideal simulated moving-bed (SMB) chromatography derived previously revealed important new properties of the SMB process. This solution was validated by comparing with experimental data and with the results of numerical solutions of the equilibrium-dispersive and the lumped kinetic model. This earlier solution, however, was limited to the simple case in which the safety factor was assumed to be the same for the flow rates in all four sections. An extension of this solution to the case in which the safety factors differ and allow an independent selection of the four different flow rates (within limits) is derived. This solution accounts well for most practical situations. It permits the discussion of the influence of different flow rates on the performance of an SMB unit, an issue of critical importance for the optimization of the design and operation of these separators.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690431109
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...