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  • Chromatography
  • Wiley-Blackwell  (18)
  • American Chemical Society  (1)
  • Springer Science + Business Media
  • 1
    Publication Date: 2022-05-27
    Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Gosselin, K. M., Nelson, R. K., Spivak, A. C., Sylva, S. P., Van Mooy, B. A. S., Aeppli, C., Sharpless, C. M., O’Neil, G. W., Arrington, E. C., Reddy, C. M., & Valentine, D. L. Production of two highly abundant 2-methyl-branched fatty acids by blooms of the globally significant marine cyanobacteria Trichodesmium erythraeum. ACS Omega, 6(35), (2021): 22803–22810, https://doi.org/10.1021/acsomega.1c03196.
    Description: The bloom-forming cyanobacteria Trichodesmium contribute up to 30% to the total fixed nitrogen in the global oceans and thereby drive substantial productivity. On an expedition in the Gulf of Mexico, we observed and sampled surface slicks, some of which included dense blooms of Trichodesmium erythraeum. These bloom samples contained abundant and atypical free fatty acids, identified here as 2-methyldecanoic acid and 2-methyldodecanoic acid. The high abundance and unusual branching pattern of these compounds suggest that they may play a specific role in this globally important organism.
    Description: This work was funded with grants from the National Science Foundation grants OCE-1333148, OCE-1333162, and OCE-1756254 and the Woods Hole Oceanographic Institution (IR&D). GCxGC analysis made possible by WHOI’s Investment in Science Fund.
    Keywords: Lipids ; Alkyls ; Bacteria ; Genetics ; Chromatography
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Chemometrics 5 (1991), S. 417-434 
    ISSN: 0886-9383
    Keywords: Factor analysis ; Power density distribution ; Chromatography ; Absorption spectroscopy ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Evaluation of the results of factor analysis of sets of spectroscopically detected chromatograms is carried out by examining the shapes of the abstract factors. This is done either by visual inspection or by analysis of the power density spectra produced from them. Owing to constraints imposed by the column function and the spectroscopic instrument function, the information content of the chromatograms necessarily occurs at low spatial frequencies. As a consequence, it appears as relatively broad features in the abstract chromatograms and as a peak in the low-frequency region of the corresponding power density plot. On the basis of examination of the power density distribution, a well-defined distinction is made between primary and secondary abstract factors. The major uncertainty encountered in determining the number of chemical components appears to arise from effects of contaminants in reagents.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 1 (1978), S. 41-46 
    ISSN: 0935-6304
    Keywords: Chromatography ; Theory ; Chromatographic systems analysis ; Real plate number ; Fundamental interpretation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The real plate number concept is interpreted in terms of the fundamental properties of a chromatograph. It is shown that the linear relationship between the total peak width at half height, (b0.5)T, t, and k is only an approximation of the more general linear relationship between (b0.5)2T, t and (1 + k)2. In the case where the relationship between (b0.5)T, t and k approaches linearity, it is concluded, firstly, that b0 = a, i. e., b0 is a column property and independent of extra-column phenomena and, secondly, that nreal=ntheor. When the relationship becomes non-linear, b0 is determined partly by extra-column phenomena, but not in terms of a useful relationship. It is concluded that it is unnecessary to introduce the parameters a, b0 and nreal, since they all have counterparts in the established theory of chromatography. These counterparts prove to be equally useful in the practical analysis of chromatographic systems.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 9 (1986), S. 584-589 
    ISSN: 0935-6304
    Keywords: Chromatography ; Additivity of sorption energy ; Universal equation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Deviations from the additivity of energy contributions to substance sorption energies, determined on the basis of thermodynamic studies of GC behavior of homologous series of organic compounds fall into two categories: one for n-alkanes, the other for homologous series containing a functional group. A previously derived equation is proposed for homologous series, describing the deviation from the linear dependence of retention parameters with a propagating homolog n-alkyl chain. The equation permits calculation of retention parameters of homologs starting from the first member in gas-liquid, gas-solid, and liquid-liquid systems. The results prove its universal applicability.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 16 (1993), S. 258-261 
    ISSN: 0935-6304
    Keywords: Nomenclature ; Chromatography ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The background of the new Unified Nomenclature for Chromatography just accepted by the International Union of Pure and Applied Chemistry (IUPAC) is explained and selected highlights of the new rules are elaborated.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 7 (1984), S. 118-122 
    ISSN: 0935-6304
    Keywords: Chromatography ; Terminal band length ; Band spreading ; Theoretical plates ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A terminal band length is defined here as the length of a dispersed solute band as it emerges from the chromatographic column. The number of terminal band lengths per column can be used in the same way that the number of theoretical plates per column is used to measure and compare chromatographic efficiencies, but with greater insight since the proposed unit of measure is an easily visualized, real entity. In addition, the height equivalent to a theoretical plate (HETP) can be regarded as a ratio of the terminal band lenght to sixteen times the number of equivalent terminal band lengths that could be contained in tandem in the column. This concept offers another approach to understanding the meaning of the term, HETP. The terminal band length of a series of homologues is constant and independent of retention time above a certain solute molecular size and column capacity ratio. Within those conditions the correlation between the recorded peak width and retention time during isothermal analysis occurs primarily as a result of change in solute velocity.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 315-317 
    ISSN: 0935-6304
    Keywords: Chromatography ; Quantitative Analysis ; Computer calculation of peak areas ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Quantitative chromatographic analysis is liable to errors due to peak asymmetry because the uncertainty in the detected position of the end of the peak tail decreases the reliability of the computed peak area. This dependence may be a severe drawback whenever peaks of different areas must be compared, as in the case of calibration curves. A new approach to overcome the uncertainties of area calculation due to peak asymmetry is reported in this paper. The approach consists of calculating only the area included between the start and the maximum of the chromatographic peak. Simulated and experimental chromatographic data were used in this study. Both the peak start-to-peak maximum area (SMA) and the start-to-end or total area (TA) were calculated and the quantitative results were compared. Within the scope of this work it is concluded that the SMA yields calibration curves that are more linear and have intercepts closer to zero than the calibration curves obtained using the TA.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 2 (1979), S. 193-194 
    ISSN: 0935-6304
    Keywords: Chromatography ; Theory ; Resolution equations ; Comparison and evaluation; equation (4) preferred ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 4 (1981), S. 99-101 
    ISSN: 0935-6304
    Keywords: Chromatography ; Laboratory computer use ; Qualified data reduction ; Graphic display of summarized analytical results ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Use of a Hewlett-Packard 2648 A graphics terminal connected to a HP 3354 B Laboratory Automation System for drawing polygon diagrams of chromatographic data has been investigated. The computer program is designed to reduce polygon overlapping and hiding by fully automatic parameter adjustment.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 7 (1984), S. 245-251 
    ISSN: 0935-6304
    Keywords: Chromatography ; Temperature programming ; Efficiency ; Resolution ; Solute mobility ; Threshold temperature ; Emergence temperature ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The threshold temperature for solute mobility is defined as that temperature at which a solute band, which was initially cold trapped at the head of the column, begins moving through the column. It is shown that the separation of compounds by programmed temperature gas Chromatography (PTGC) occurs primarily at the head of the column as a result of differences in threshold temperatures. Additional column length beyoud that needed to trap the compounds improves resolution, primarily by delaying emergence (while maintaining the temperature and time spacing) thus allowing the column temperature to rise, the solute terminal velocities to increase, and narrower peak widths to be recorded. For maximum resolution in minimum analysis time, the initial temperature must be at or below the threshold temperature of the most volatile compound in the mixture to be separated.Three methods for determining threshold temperatures are presented.
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  • 11
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electrophoresis 18 (1997), S. 2928-2934 
    ISSN: 0173-0835
    Keywords: Separation factor ; Capacity factor ; Capillary electrophoresis ; Chromatography ; Ultracentrifugation ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Understanding the separation process in capillary electrophoresis (CE) leads to the unification of the theories for separation science. While the separation of analytes is governed by equilibria in chromatography, and by (centrifugal) field in ultracentrifugation, the separation in CE is governed by both equilibria and (electric) field. Therefore, a comprehensive separation theory that describes the separation process of analytes in CE should be able to describe the separation processes in both chromatography and ultracentrifugation. In this paper, we propose that individual capacity factors for each analyte species be used to describe the migration behavior of an analyte. The effect of field on each analyte species, as well as the effect of equilibria are considered in deriving a generalized equation that is applicable for all separation techniques. The separation factor defined at present does not directly relate to the migration rates of the analytes, and therefore can not be used in a generalized theory. We propose that the ratio of the migration rates of a pair of analytes (γ) should be used as the separation factor, instead of the ratio of the two capacity factors. When γ is used to describe the separation of two closely migrating analytes, all separation techniques have the same resolution equation.
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  • 12
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 254-260 
    ISSN: 0570-0833
    Keywords: Chromatography ; Polyamides ; Separation ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Columns of polyamide are well suited for chromatographic separation of numerous organic compounds, especially phenols, carboxylic acids, and aromatic nitro compounds. The method is also useful for isolating naturally occurring compounds on a preparative scale. The affinity of phenols for polyamides is due to the formation of hydrogen bonds to the peptide linkages of the polyamide, while aromatic nitro compounds are retained by means of free amino groups in the polymer. Quinones react irreversibly with the free amino groups of the polyamide. Quinones are not retained by acetylated polyamides although phenols are.
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  • 13
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 25 (1986), S. 535-552 
    ISSN: 0570-0833
    Keywords: HPLC (high pressure liquid chromatography) ; Proteins ; Analytical methods ; Chromatography ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The application of high-pressure liquid chromatography (HPLC) to proteins has undergone a dramatic development in recent years. Nowadays its many variants expand the repertoire of high-performance analysis methods available to the protein chemist, which, until now, have been dominated by electrophoretic techniques. The advent of gene technology has resulted in a renaissance of protein chemistry. The new analytical and preparative problems that have thereby emerged are often ideally solved by HPLC methods. HPLC has long since ceased to be solely a laboratory technique; HPLC systems are now being developed for the separation of proteins-particularly those of great pharmaceutical interest - on a 100-g scale. The range of applications of analytical and preparative HPLC will be illustrated by two examples of pharmaceutical importance - insulin and interleukin 2.
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  • 14
    ISSN: 0173-0835
    Keywords: Human serum albumin ; Conformation ; Drug ; Ligand ; Phenyl-agarose ; Affinity electrophoresis ; Hydrophobic interaction immunoelectrophoresis ; Chromatography ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Analysis of normal human serum by crossed hydrophobic interaction immunoelectrophoresis with Phenyl-Sepharose revealed a biphasic appearance of the albumin peak. The molecular mechanism behind this apparent albumin heterogeneity was investigated. Analysis of defatted purified albumin showed that a major fraction bound to the Phenyl-Sepharose and that addition of ligands (e.g. long-chain fatty acids, bilirubin, sulfonamides and warfarin) before electrophoresis blocked this binding to different degrees. A quantitative relation between ligand binding and the amount of nonbinding albumin was found. Thus the technique might be suitable for screening of ligand binding to albumin. Analysis of serum samples from newborns with hyperbilirubinemia revealed a positive correlation between the fraction of the nonretarded albumin and the bilirubin concentration. By chromatography on Phenyl-Sepharose, defatted albumin was separated into a binding and a nonbinding from and this technique was subsequently used to determine the kinetics of the intramolecular conversion. After rechromatography, each of the fractions could again be separated into two fractions, indicating the presence of an eqilibrium. By varying the passage time for albumin on the column or varying the period between the first and the second separation it was possible to calculate the conversion rates. The half-life for the conversion was found to be as long as 1 ¼ h. It is the first time that a conformational change for albumin with such a long conversion time has been described experimentally.
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  • 15
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 19 (1980), S. 13-24 
    ISSN: 0570-0833
    Keywords: Chiral resolution ; Analytical methods ; Chromatography ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A number of racemates can be resolved into optically pure enantiomers by chromatography on optically active adsorbents. Synthetic polymers with optically active amide, amino acid, and crown ether groups, natural products such as starch and cellulose, and also microcrystalline triacetylcellulose are suitable for this purpose. Racemates can also be resolved by gas chromatography on optically active stationary phases.
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  • 16
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 17 (1978), S. 738-746 
    ISSN: 0570-0833
    Keywords: Chromatography ; Supercritical fluids ; Analytical methods ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chromatography with supercritical fluids unites the features of both gas chromatography and liquid chromatography, yet retains special characteristics of its own. The diffusion coefficient and particularly the viscosity of fluid phases may approach values for low-pressure gases, while the solvent power may be similar to that of liquids. However, with supercritical fluids it is possible to control chromatographic separations very effectively by pressure programming, since the solubility increases with increasing density. Temperature programming, on the other hand, can have the opposite effect to that in gas- or liquid-chromatography since the density decreases with increasing temperature at a given pressure. Supercritical fluid chromatography is primarily of interest for the separation of higher molecular weight compounds. The efficiency of this method of separation is demonstrated on several homologous series. Thus, a styrene oligomer with nominal Mw=2200 can be resolved by a pressure and temperature program into 40 species.
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  • 17
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 21 (1982), S. 50-61 
    ISSN: 0570-0833
    Keywords: Chromatography ; HPLC (high pressure liquid chromatography) ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: After a decade, the first storm of development in high performance liquid chromatography seems to be abating. Providing the stationary phase and eluent are optimized, most routine analytical and semi-preparative separation problems require columns having between 1000 and 10000 theoretical plates. Commercial apparatus and columns completely satisfy these requirements. For many separation problems the efficiency of the columns on offer is greater than required. Since optimal (not maximal) separation is required with shorter analysis times, the column inlet pressure is increased in order to increase the eluent velocity, while at the same time reducing the column efficiency. The same result can be obtained by using shorter columns and lower pressures. Since inlet pressures of more than 100 bar are seldom required in routine analysis, the term “high pressure liquid chromatography” is a misnomer. - It is probable that difficult separation problems, where several 100 000 theoretical plates are required, will be studied in the next phase of development. It can be shown using nomograms that such problems can be solved within acceptable time limits using inlet pressures of less than 500 bar. Further possible directions of development are indicated.
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  • 18
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 24 (1985), S. 451-465 
    ISSN: 0570-0833
    Keywords: Mass spectrometry ; Metabolism ; Analytical methods ; Chromatography ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Powerful separation methods developed during the past few decades, in particular glass capillary gas chromatography (GC) and high performance liquid chromatography (HPLC), can be combined with sensitive methods of detection such as mass spectrometry (MS) to provide new insights into metabolic processes. Research in a field that was long thought to be exhausted has thus been revitalized. New perspective have been opened up for studying the metabolism of foods, spices and flavorings, drugs, and compounds produced in the body as well as for establishing the way in which the organism rids itself of harmful substances or how and when these compounds can interfere with the metabolic processes occurring in the body.
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  • 19
    ISSN: 0570-0833
    Keywords: Chromatography ; Gel filtration ; Separation ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Over the past few years, fractionation of mixtures of substances on the basis of differences in their molecular weights has become an important method in chemistry and biochemistry. A survey is given of the theory and practice of separations applying porous gels, and the multifarious uses of such gels are indicated.
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