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  • 2020-2023
  • 1975-1979  (15)
  • 1960-1964  (3)
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  • 1978  (15)
  • 1963  (3)
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  • Gas chromatography
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Erscheinungszeitraum
  • 2020-2023
  • 1975-1979  (15)
  • 1960-1964  (3)
  • 1955-1959
  • 1950-1954
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Jahr
  • 1
    ISSN: 1432-2072
    Schlagwort(e): Cholinergic function ; Acetylcholine ; Choline ; Levels ; Turnover rates ; Gas chromatography ; Lead poisoning ; Malnutrition ; Central nervous system
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Rats were exposed to lead acetate from birth, and were killed at the age of 44–51 days for analysis of levels and turnover rates of acetylcholine (ACh). Steady-state levels of ACh were not altered in midbrain, cortex, hippocampus, or striatum of lead-exposed rats. Similarly, no changes in choline (Ch) concentrations were found in cortex, hippocampus, or striatum. In the midbrain, however, a 30% reduction in Ch levels was observed. Changes in specific activity of Ch and ACh were measured as a function of time in selected brain areas of rats infused with a radio-labeled precursor of Ch. Specific activities of ACh were not altered. Ch specific activities were, however, significantly elevated in all brain areas examined, as compared with age-matched control rats. The in vivo ACh turnover rate in cortex, hippocampus, midbrain, and striatum was diminished by 35%, 54%, 51% and 33%, respectively. These findings provide direct evidence for an inhibitory effect of lead exposure from birth on central cholinergic function in vivo. Since a significant reduction of body weight was found in those animals treated with lead acetate, the alteration of central cholinergic function may partially be attributed to malnutrition observed in the lead-exposed animals.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 57 (1978), S. 77-81 
    ISSN: 1432-2072
    Schlagwort(e): Dihydroxyphenylacetic acid ; Homovanillic acid ; Dopamine ; Gas chromatography ; Caudate ; Globus pallidus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The relationship of human brain levels of 3,4-dihydroxyphenylacetic acid (DOPAC) to cerebrospinal fluid levels of this dopamine (DA) metabolite was studied. The effect of postmortem delay was evaluated in the rat. DOPAC was resistant to postmortem changes in brain kept in situ. The level of DOPAC (free and conjugated) determined in DA-rich areas of six human brains amounted to only a fraction of the homovanillic acid (HVA) found in the same regions. The DOPAC/HVA ratio in human brain was similar to that found in CSF. We conclude that HVA is the major DA metabolite in human brain and that DA metabolite levels in CSF reflect DA metabolite levels in brain.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    International archives of occupational and environmental health 41 (1978), S. 7-15 
    ISSN: 1432-1246
    Schlagwort(e): Gas chromatography ; Industrial solvents ; Methylchloroform ; Vestibular disturbances
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A previously described experimental model for studying the effects on the central nervous system of rabbits, specifically the vestibular apparatus, has been applied to methylchloroform. To achieve a steady concentration the solvent was infused as a lipid emulsion. The blood and cerebrospinal fluid kinetics have been studied. The arterial blood level seems to be closely correlated to the concentration in the central nervous tissue. Vestibular function has been studied by recording the involuntary eye movements — nystagmus — which are elicited via central vestibulo-oculomotor connections. At blood levels of methylchloroform above 75 ppm a so called “positional nystagmus”, indicated vestibular disturbances, is demonstrated. The relationship between the present findings in rabbits and the reaction and blood concentrations in people exposed to industrial solvents, are discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Pflügers Archiv 375 (1978), S. 161-165 
    ISSN: 1432-2013
    Schlagwort(e): Gas chromatography ; Helium ionization detector ; Inert gases ; Methods ; Solubility
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A method for quantitative analysis of inert gases in liquids by gas chromatography is described. The technique comprises an equilibration system for partial extraction of dissolved gases from liquids and a gas chromatograph equipped with helium ionization detector. The method is particularly devised for determination of solubility coefficients of gases in liquid materials, e. g. water, aqueous solutions, blood, tissue homogenates, and for simultaneous measurement of several inert gases dissolved in liquids. Coefficients of variation for serial analyses of individual samples were ≦ 3%. The method is applicable to studies of blood-tissue transfer of respiratory and inert gases.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    European journal of pediatrics 127 (1978), S. 269-278 
    ISSN: 1432-1076
    Schlagwort(e): Classical phenylketonuria ; Hyperphenylalaninemic variants ; Protein challenge ; Urinary aromatic acids ; Gas chromatography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A protein challenge (3 g/kg) was given to 15 hyperphenylalaninemic patients for 4 days and urinary excretion of aromatic phenylalanine metabolites (e.g. phenylpyruvic acid; mandelic acid; ortho-hydroxy-phenylatic acid) was studied by quantitative gas chromatographic analysis. Two groups of patients, different in their serum phenylalanine pattern, could be distinguished from the pattern of urinary aromatic acid excretion. In the first group, the aromatic acid excretion decline towards the end of the challenge whereas aromatic acid excretion increased throughout the challenge in the second group. The differences could be ascertained by statistical analysis.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 1 (1978), S. 200-201 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Control of relative retention in series-coupled columns by temperature variation ; Effect of temperature variation on OV 101/Silar 5 column pair ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 1 (1978), S. 217-218 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Quantitative analysis of cholesterol ; Stigmasterol as internal standard ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 1 (1978), S. 227-228 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Septa, column inlet ; Damage to septum by syringe needle ; Column contamination as result of septum damage ; Pre-drilling of septum ; Modification of syringe needle tip ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 1 (1978), S. 301-301 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass, rapid preparation ; Quartz powder surface roughening ; Ideal for thick film impregnations ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 1 (1978), S. 302-303 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; Testing uncoated columns ; Test with precolumn ; Adsorption, and acid/base effects ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 11
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 1 (1978), S. 199-200 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Controlling relative retention by mixed mobile phases ; Steam plus nitrogen ; Linear relationship for precise analytical forecast of optimum fractional partial pressure ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 12
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 1 (1978), S. 223-224 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Precolumn techniques ; Multifunctional timer for preselection of switching operations ; Variable operating range ; Versatility of application ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 13
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 1 (1978), S. 225-225 
    ISSN: 0935-6304
    Schlagwort(e): Liquid chromatography ; Gas chromatography ; Stationary phase macroporous co-polymer type SEPARON ; Reproducible controlled microstructure with interconnected pores ; Reversed phase type for HPLC ; Up to 230°C in GC ; For trapping traces from water samples ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 14
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 1 (1978), S. 211-212 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; Subambient temperatures ; Cryogenic unit, inexpensive ; Temp. programming from ca. -50°C ; Automobile exhaust analysis, improved separation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 15
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 1 (1978), S. 263-267 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; On-column injection ; Recommendations for users ; Sample size 0.1-8.0 μl ; Optimization ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: During one year continuous use of on-column injection, the typical advantages described in our first report have fully been confirmed. In addition the analysis of large sample volumes has proved promising. Only minor modifications have been applied to the on-column injector device. Broad evidence has been gathered showing that full separation efficiency of the capillary columns after on-column injection is attained only when cold trapping or the solvent effect, as band shortening mechanisms, are working- While, under the conditions of on-column injection, cold trapping is less efficient than with other injection techniques, the opposite holds true for the solvent effect. Compared with splitless injection, the danger of excessive solvent condensation on the column is increased. A working rule is presented for establishing the optimal chromatographic conditions for handling large sample volumes while ensuring full separation efficiency yet avoiding harm to the column.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 16
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 515-523 
    ISSN: 0570-0833
    Schlagwort(e): Permethylation ; Carbohydrates ; Methylation ; Gas chromatography ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Methylation of mono-, oligo-, and polysaccharides with methyl iodide/barium oxide or dimethyl sulfate/barium hydroxide in dimethyl sulfoxide as solvent rapidly leads to high degrees of methylation. Depending on the structure and solubility of the substrate, permethylation can be achieved either in one operation or by repetition of the same treatment. Procedures of permethylation of various carbohydrates are given. The methyl glycosides obtained on methanolysis can be separated and determined quantitatively by gas chromatography. The preparation of separating columns with minimum retention for this purpose is described. Pullulan was shown to have the structure of a completely linear polymer of maltotriose units connected by α-1→6-linkages. - In addition the gaschromatographic identification of methyl ethers of glucosamine and galactosamine is reported.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
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  • 17
    ISSN: 0570-0833
    Schlagwort(e): Radiocarbon ; Gas chromatography ; Trace analysis ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: In biochemical work with isotopic tracers, it is frequently advantageous to investigate samples in the gas phase. In this way, the selectivity of gas-chromatographic separating columns and the sensitivity of detectors can be utilized for both the detection of gas-chromatographic fractions and the determination of their radioactive portions. Conversion of materials separated by gas chromatography into a single standard chemical compound prior to measurement of the radioactivity is recommended. Methods suitable for 14C-labelled compounds can also be applied to those labelled with 3H or 35S.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 18
    ISSN: 0570-0833
    Schlagwort(e): Racemization ; Peptide synthesis ; Gas chromatography ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: It is shown that the methyl esters of many diastereoisomeric N-trifluoroacetyldipeptides can be separated by gas chromatography on Golay columns. This makes it possible for the first time to carry out accurate quantitative investigations of recemization occurring during peptide synthesis without resort to measurements of optical rotation or enzymatic cleavage, and witout having to isolate the peptides. Some well-known methods of forming peptides were examined using the synthesis of the methyl ester of carbobenzoxy-L-valyl-L-valine as an example. The synthesis of the methyl ester of N-trifluoroacetyl-L-valyl-L-valine was investigated as a model for the linking of peptides. The influence on racemization of numerous factors was determined. General conclusions could be drawn regarding peptide synthesis.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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