ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • Analytical Chemistry and Spectroscopy  (17)
  • Biochemistry and Biotechnology  (13)
  • 1995-1999  (18)
  • 1975-1979  (12)
Collection
Publisher
Years
Year
  • 1
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Chemical ionization mass spectrometry of the title compounds demonstrates that the formation of the [M+H—CH3OH]+ ions is strongly influenced by the degree as well as the type of alkyl substitution of the α-carbon atom. The extent of cyclization (i.e. formation of [M+H—CH3OH]+) closely resembles that of the activated esters in condensed phases.
    Notes: Art und Anzahl der Alkylsubstituenten am α-C-Atom der Titelverbindungen beeinflußen in entscheidender Weise die durch chemische Ionisation induzierte Methanol-Eliminierung aus den [M + H]+-Ionen. Die Cyclisierungstendenz entspricht sehr stark der von aktivierten Estern in kondensierter Phase.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 0935-6304
    Keywords: Capillary electrophoresis ; Enantiomeric separations ; Acidic compounds ; Neutral β-cyclodextrins ; Sulfobutyl ether β-cyclodextrin ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High resolution could be achieved for the enantiomers of acidic drugs, namely, sulindac, fenoprofen, ketoprofen, warfarin, and hexobarbital, in a buffer of pH 3 by the simultaneous addition of uncharged and charged β-cyclodextrin derivatives. The interaction of the analytes with the anionic sulfobutyl ether β-cyclodextrin provides the analytes with an adequate electrophoretic mobility whereas the interaction with various neutral β-cyclodextrins generates high enantioselectivity. Five neutral cyclodextrins, the native β-cyclodextrin, as well as methyl-, dimethyl-, trimethyl- and hydroxypropyl-β-cyclodextrin, were tested to enhance the enantioselectivity of the electrophoretic system. High resolution values and the shortest analysis times for the five drugs tested were achieved in a buffer made of 100 mM phosphoric acid adjusted to pH 3 with triethanolamine and containing dimethyl- or trimethyl-β-cyclodextrin in addition to sulfobutyl ether β-cyclodextrin.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 37-42 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The headspace gas in static headspace gas chromatography contains mostly saturated water vapor. In the case of the cryofocusing enrichment technique this may cause baseline distortion in the early part of the chromatogram or may even lead to ice-plugging of the capillary column. A water-trap is described in which the water vapor is removed from the headspace gas before entering the cryo-trap. The water trap is packed with lithium chloride on a porous support and is regenerated after each analysis by heating under backflush conditions. It therefore can be used for automatic operation. Data are given for the precision and accuracy, and some practical examples, for environmental and flavor analysis are shown.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 51 (1996), S. 15-22 
    ISSN: 0006-3592
    Keywords: preparative separation ; continuous ; free-flow zone electrophoresis ; electrophoretic mobility ; net charge ; enzymes ; proteins ; crude extract ; cell debris ; Candida boidinii ; Escherichia coli ; formate dehydrogenase ; formaldehyde dehydrogenase ; methanol oxidase ; β-galactosidase ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Continuous, single-step, state-of-the-art preparative separations of enzymes from microorganism crude extracts by free-flow zone electrophoresis are presented. In the first example, the enzymes formate dehydrogenase, formaldehyde dehydrogenase, and methanol oxidase were continuously separated from Candida boidinii crude extract. Yields of 85% to 95% and purification factors between 3 and 7 were obtained along with a simultaneous separation of the finer cell debris from the enzymes. Using multiple injections of sample, a throughput of 46.2 mg protein/h was recorded. In the second example, a fivefold purification of β-galactosidase from Escherichia coli was achieved along with complete, simultaneous cell debris separation from the enzyme. The yield of the enzyme was greater than 90%. The preparative free-flow zone electrophoresis experiments were run continuously for a period of 12 h and the separations were found to be stable; i.e., the enzymes and the cell debris eluted at their respective fraction numbers during the entire period. In both examples, choice of the type of buffer played a critical role and had to be investigated and optimized experimentally. Scale-up aspects of the separations are also discussed. Recently, by comparison of free-flow zone electrophoresis with ion-exchange chromatography, we have presented evidence that free-flow electrophoresis separations are governed by net surface charge (S. Nath et al., Biotechnol. Bioeng. 1993, 42: 829-835). Here, we offer further confirmation of this evidence by comparison of preparative free-flow zone electrophoresis experiments at various pHs on a mixture of two model proteins with analytical electrophoretic titration curves of the proteins. We are thus in a position to predict separations in free-flow zone electrophoresis. © 1996 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The qualitative and quantitative determination of cholesterol and 7-dehydrocholesterol (7-DHC) in plasma as a biochemical diagnostic marker for the Smith-Lemli-Opitz syndrome by liquid chromatography/particle beam interface-mass Spectrometry (LC/PB-MS) is presented. Baseline separation of cholesterol arid 7-DHC is achieved on a silica column with hexane + ethanol (99:1 v/v) as mobile phase within a 10 min analysis. Recoveries of cholesterol and 7-DHC in a simple two-phase extraction system are nearly 100%. The absolute limit of detection using LC/PB-MS is ≈10 ng. The method presented allows extraction, analysis and quantification of cholesterol and 7-DHC within 15 min without the necessity of sample derivatization.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of androstan-3,16,17β-triols are very similar, so that a distinction between isomers is rather difficult. Main degradation reactions correspond to expulsion of substituents and loss of parts of the D-ring system.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 4 (1977), S. 155-158 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mass spectra of antipyrine metabolites show characteristic fragmentation patterns which depend on the presence and position of functional groups. A substituent at position 4 is indicated by an intense key fragment at m/e 56 and a substituent at the methyl group in position 3 causes a significant increase in the intensity of the peak at m/e 82. The fragment at m/e 96, which is characteristic for antipyrine itself, is suppressed if there is a substituent in either position 3 or 4. Mass spectra of the glucuronides of 4-hydroxyantipyrine and 3-hydroxymethylantipyrine are also discussed.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 20 (1997), S. 55-61 
    ISSN: 0935-6304
    Keywords: Enantioselective gas chromatography ; Essential oils ; Authenticity control ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The potential of enantioselective capillary gas chromatography with modified cyclodextrins as chiral stationary phases for authenticity control is demonstrated for a selection of economically important essential oils. Adulteration can be easily detected in cases where enantiomerically pure constituents are present in natural oils. In cases of (naturally) varying enantiomeric compositions of chiral constituents, enantioselective gas chromatography may prove insufficient.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 0173-0835
    Keywords: Free flow electrophoresis ; Isoelectric focusing ; Two-dimensional polyacrylamide gel electrophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A whole cell lysate of human cells was separated into 80 fractions according to the pI of proteins using free flow isoelectric focusing with carrier ampholytes. The resolution of the process was highly reproducible, with an overlap of fractions of less than 30%. A protein of a faint silver stained spot in two-dimensional gel electrophoresis (2-DE) could be enriched, yielding a Coomassie blue stained spot which could be further characterized by proteinchemical methods. The enrichment of less abundant proteins from a complex crude cell extract was found to be a suitable tool for sample preparation and enrichment before applying proteins to 2-DE and reversed-phase high performance liquid chromatography.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Electrophoresis 19 (1998), S. 3090-3093 
    ISSN: 0173-0835
    Keywords: Preparative electrophoresis ; Interval preparative isotachophoresis ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: A new preparative electrophoretic method in free solution is described, consisting of three consecutive steps: (i) filling the separation chamber with a suitable electrolyte system and sample in parallel streams by laminar hydrodynamic flow, (ii) applying the voltage across the chamber with isotachophoretic separation for a definite time interval operating in the direction perpendicular to that of filling, (iii) reapplying a hydrodynamic flow (without voltage) and collecting the separated species via an array of outlets. This approach completely eliminates the main drawback of the continuous flow electrophoresis (CFE), i.e., the electrohydrodynamic distortion of zones. This method utilizes the instrumentation devised for CFE and enables the isolation of large amounts of individual sample species comparable to that of CFE, with a resolution comparable to that of capillary isotachophoresis. The precise timing of the consecutive steps in the procedure as well as the stability of the operational parameters are of key importance for reproducibility. By using cationic isotachophoresis with 3 synthetic pI markers as model sample species, the reproducibility, stability and the separation power of the newly presented method are demonstrated. The sample throughput corresponds to micromoles per hour.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...