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  • 1990-1994
  • 1980-1984  (634)
  • 1980  (634)
  • Physics  (558)
  • Gas chromatography
  • Nuclear reactions
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    International archives of occupational and environmental health 45 (1980), S. 153-161 
    ISSN: 1432-1246
    Schlagwort(e): Pentachlorophenol ; High-performance liquid chromatography ; Gas chromatography ; Biological monitoring ; Pentachlorphenol ; Hochdruck-Flüssigkeits-Chromatographie ; Gaschromatographie ; Biological monitoring
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Für die Bestimmung von freiem Pentachlorphenol in der Luft und im Blut wurden leistungsfähige chromatographische Routineverfahren ausgearbeitet. Für die Raumluftbestimmung wird Pentachlorphenol durch Einleiten von Luft in einer Vorlage angereichert und nach Aufarbeitung in freier Form durch Hochdruck-Flüssigkeits-Chromatographie quantitativ erfaßt. Alternativ kann die Analyse nach Derivatisierung durch Kapillar-Gaschromatographie erfolgen. Freies Pentachlorphenol im Vollblut wird nach Aufarbeitung und Derivatisierung durch Kapillar-Gaschromatographie in Verbindung mit dem Elektroneneinfang-Detektor quantitativ bestimmt. Bei den beschriebenen chromatographischen Methoden sind die Eichkurven über den angegebenen Konzentrationsbereich linear. Die gaschromatographische Trennung blieb über den gesamten Untersuchungszeitraum völlig reproduzierbar. Die problemlose Derivatisierung läßt die beschriebene gaschromatographische Methode in Verbindung mit einem automatischen Probengeber für das biological monitoring auch größerer Kollektive geeignet erscheinen.
    Notizen: Summary Efficient chromatographic procedures for the determination of free pentachlorophenol in air and in blood have been developed. Free pentachlorophenol from the indoor environment is preconcentrated in an impinger. Following a simple extraction, it is detected by high performance liquid chromatography without derivatisation. An alternate method is capillary gas chromatography of a suitable derivative. Unchanged pentachlorophenol in whole blood is similarly derivatised and determined quantitatively by capillary gas chromatography using an electron capture detector. The calibration curves of the described chromatographic methods were linear within the specified concentration range. Reproducibility of gas chromatographic separation remained unchanged during the whole research period. Owing to its relative simplicity, the described gas chromatographic method is advantageous for the biological monitoring of large collectives.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Archives of toxicology 44 (1980), S. 291-297 
    ISSN: 1432-0738
    Schlagwort(e): Tetrodotoxin ; 2-Amino-6-hydroxymethyl-8-hydroxyquinazoline ; (C9-base) ; Gas chromatography ; Mass spectrometry ; Autopsy material
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Eine gaschromatographische Methode zum Nachweis von Tetrodotoxin im Obduktionsmaterial wird beschrieben. Das Derivat (2-Amino-6-hydroxymethyl-8-hydroxychinazolin, C9-Base), das sich durch die Einwirkung der Alkalilauge auf Tetrodotoxin gewinnen ließ, wurde schließlich durch Gaschromatographic nachgewiesen. Die Massenspektren der trimethylsilyerten C9-Base werden neben den Ergebnissen der gaschromatographischen Untersuchung von acht tödlichen Intoxikationsfällen angegeben.
    Notizen: Abstract A gas Chromatographic method for the detection of tetrodotoxin in autopsy material is described. The derivative (2-amino-6-hydroxymethyl-8-hydroxyquinazoline, C9-base), which was obtained from tetrodotoxin by alkali treatment, was finally detected by gas chromatography. The mass spectra of the trimethylsilylated (TMS) C9-base are presented together with the result of a gas Chromatographic investigation of 8 cases of fatal intoxication.
    Materialart: Digitale Medien
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  • 3
    ISSN: 1432-1076
    Schlagwort(e): Phenylketonuria ; Phenylpyruvic acid ; Phenylacetates ; Gas chromatography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract There is a steady and nonlinear relationship between the levels of both phenylpyruvic acid (PPA) and o-hydroxyphenylacetic acid (oOPAA) in urine and the plasma levels of phenylalanine (phe) in children more than two years of age with phenylketonuria (PKU). If phe levels in blood rise above 0.35 mM (5.8 mg/100 ml) both aromatic acids are found regularly in urine. Typically, urinary concentrations of PPA are about 5 times higher than those of oOPAA. This report is based on the analysis of 94 samples from 51 children, on or off diet.
    Materialart: Digitale Medien
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  • 4
    ISSN: 1432-2048
    Schlagwort(e): Boron ; Foliar nutrition ; Nuclear reactions ; Transport (boron) ; Trifolium
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The growth of white clover (Trifolium repens L.) is severely inhibited by boron starvation, but a foliar treatment with boric acid can transitorily alleviate the deficiency symptoms. The 10B(n ,α)7 Li nuclear reaction has been used to study boron transport in the plant after foliar application. More than 98% of the boron supplied remained at the point where it was applied to the leaves, and less than 2% was useful to the growth of the treated plant. This small “efficient” portion of boron was quite mobile. It was distributed to the different parts of the plant, then was transferred from the oldest parts to the newly formed leaves. Physiological and agronomical implications of these data are discussed.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 211 (1980), S. 73-82 
    ISSN: 1432-0878
    Schlagwort(e): Preputial glands ; Nude mice ; Ultrastructure ; Gas chromatography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The preputial glands of male nude (nu/nu) mice were analyzed by a combination of electron microscopy and gas chromatography to determine whether or not they are affected, like developing hairs and nails, by the nu/nu genotype. Results of the analyses revealed no differences between the glands of nude and normal male mice in either their ultrastructural characteristics or lipid secretory products.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 13 (1980), S. 203-206 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Carrier gas purity ; Sample stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The amount of oxygen which may be present in the gas volume corresponding to a peak is investigated and compared to the sample amounts. It is shown that even with high purity carrier gases one may have a significant excess of oxygen present at low sample amounts. Attention is drawn to the possibility of impurity build-up by diffusion e.g. through the septum.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 13 (1980), S. 263-270 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Metal complexes ; Enantiomers ; Isotopic composition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The high selectivity of complexation gas chromatography has been employed for enantiomer resolution and isotope separation. Thus, a chiral olefin, 3-methylcyclopentene, has been resolved analytically on optically active dicarbonyl-rhodium(I)-3-trifluoroacetyl-1R-camphorate in squalane. The deuterated ethylenes C2H4−nDn have been separated on the same rhodium(I)-containing stationary phase. The chiral aliphatic oxiranes epoxypropane andtrans-2,3-epoxybutane have been resolved on optically active nickel(II)-bis-3-trifluoroacetyl-1R-camphorate in squalane.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; On-column abstraction ; Aliphatic aldehydes ; Amine antioxidants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The selective on-column abstraction of aliphatic aldehydes by gas chromatographic stationary phases containing N-iso-propyl N′-phenyl-p-phenylenediamine is described.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 13 (1980), S. 35-39 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Nitromethane ; Nitroalkanes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Impurities in commercially available nitromethane have been determined by gas-liquid chromatography using six different column packings. Besides nitromethane, 1-nitropropane, 2-nitropropane, acetonitrile, methanol, small amounts of ethanol and acetaldehyde have been detected. The presence of formaldehyde, ethyl acetate and acetone is probable. Mixtures containing comparable amounts of the four nitroalkanes could be separated on all columns, but plots of logarithms of the retention times vs. carbon number or boiling points of the nitroalkanes or column temperatures were linear only in case of columns packed with Porapak R and Q.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 13 (1980), S. 686-692 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Micropacked columns in GC ; Microparticles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Porous silica microparticles designed for modern liquid chromatography have proven effective in gas chromatography. Columns of 35–50 cm gave plate heights as low as 3.3 particle diameters and speeds of 2400 theoretical plates per second or 500 effective theoretical plates per second. Inlet pressures up to 70 atmospheres were required using hydrogen as carrier gas. The particles as received were too retentive for fast chromatography and gave asymmetric peaks. A coating of fluorosilicone oil overcame both problems. Other coatings were less effective. Bonded phases proved less satisfactory on both counts and also gave substantially less efficient columns and greater flow resistance. Column efficiency and flow resistance were sharply dependent on physical properties of the particles. The most efficient packing was clearly spherical particles of 5–10 μm diameter with narrow size distribution, pore diamters about 50 nm, BET surface areas of 25–50 m2/g and surfaces modified with trifluoropropyl silicone. A six-component hydrocarbon sample was separated in 33 s with a resolution of 4 for the most difficult pair and in 2.6 s with a minimal resolution. Performance was limited by end effects and by available pressure so that much better performance can be expected from longer columns and higher pressures.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 13 (1980), S. 752-754 
    ISSN: 1612-1112
    Schlagwort(e): Xylenol isomers ; Gas chromatography ; Polyols and polyethers as stationary phase ; Hydrogen bonding
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Xylenol isomers can be resolved on most polyols (sugars or sugar alcohols) and polyethers (polyethylene glycol or polypropylene glycol) with hydrogen-bonding interaction. They are separated on vinical polyols which have more hydroxy hydrogen than tetrol, and even on vicinal triol when its hydroxy hydrogen is acidic (stronger proton donor). The stronger is the hydrogen bonding interaction between xylenols and the liquid phase, the better is the separation of 2,4- and 2,5-xylenol, and the poorer the separation of 2,4-and 2,3-xylenol.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 13 (1980), S. 651-660 
    ISSN: 1612-1112
    Schlagwort(e): Capillary columns, glass ; Gas chromatography ; Column preparation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Glass capillary column chromatography is the most rapidly growing part of gas chromatography. There are many complex new analytical tasks and they require special capillary columns. Fortunately there is a wide range of column preparation methods available, and they make the preparation of glass capillary columns a more varied job than that of packed columns. In this paper these methods are reviewed and suggestions are given for making task-oriented columns.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 13 (1980), S. 73-84 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Gas hold-up time ; Dead time
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The two approaches used for the calculation of the gas hold-up time and thus, the adjusted retention time are outlined, first for the restricted case when the carbon numbers of the three homologues used for the calculation are evenly spaced (c3−c2=c2−c1) and then, for the general case when (c3−c2) differs from (c2−c1). The basic difference in the philosophy of the two approaches is shown.
    Materialart: Digitale Medien
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  • 14
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Column characterization ; Oxidation ; Stationary phases
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The on-column oxidation of hydrocarbons commonly used as stationary phases in column characterization is investigated. In each case significant shifts of retention are observed, which may be negative or positive depending upon the polarity of the test solutes and the adsorptivity of the support material. In order to reduce the consequent uncertainties in the Rohrschneider [1] and McReynolds [2] polarity values, a new method of column characterization is proposed. The applicability of the new method is illustrated by a consideration of a range of silicone liquid phases.
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 13 (1980), S. 207-208 
    ISSN: 1612-1112
    Schlagwort(e): Trace determination ; Hydrogen chloride ; Ethylene oxide ; Gas chromatography ; Chlorinated solvents
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A method is described for the determination of small quantities of hydrochloric acid in two chlorinated organic solvents (CHCl3 and CCl4). An excess of gaseous ethylene oxide is added to a liquid sample; the 2-chloroethanol formed is then analyzed by gas chromatography. The procedure is simpler and more sensitive in comparison with other conventional methods. It can be modified for other organic solvents.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 13 (1980), S. 567-571 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Helium detector
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Four main factors which determine the shape and the polarity of the helium detector signal are discussed. All possible responses of this detector, both in elution and in vacancy chromatography, are presented and special attention is drawn to the intermediate region. The idea of ionization vacancy is introduced for the specific case of two components which are unresolved by the column and to which the detector responds with different sensitivity.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 13 (1980), S. 574-575 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Xylenol isomers ; Sugar derivatives as liquid phases
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Adenosine, guanosine and inosine used as liquid phases in gas chromatography permits the separation of all six xylenol isomers.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 13 (1980), S. 61-67 
    ISSN: 1612-1112
    Schlagwort(e): Optimization ; Carrier gas velocity ; Gas chromatography ; Influence of temperature on optimum velocity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Zusammenfassung Die Wahl der mittleren, linearen Trägergasgeschwindigkeit bei der Analyse von Mehrkomponentengemischen unter isothermen und temperaturprogrammierten Bedingungen wird diskutiert. Es wird gezeigt, daß stets eine Trägergasgeschwindigkeit gewählt werden sollte, die mindestens gleich, besser jedoch höher ist, als die optimale Gasgeschwindigkeit für den ersten Peak, gemessen bei der Starttemperatur (Temperaturprogramm) oder bei der eingestellten Ofentemperatur (isotherme Fahrweise).
    Materialart: Digitale Medien
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  • 19
    ISSN: 1612-1112
    Schlagwort(e): Configuration ; Chiral phases ; Gas chromatography ; Isovaline
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The D-(resp. R) configuration of isovaline (=2-ethylalanine) was proved for the peptide antibiotics antiamoebin, Tü 165 (CBS 382.62), stilbellin, samarosporin (=emerimicin IV), suzukacillin B (A), trichotoxin A-40 and A-50. This contradicts the previously reported L-configuration for isovaline in antiamoebin and emerimicin IV. The configuration was determined by GC of the N-trifluoroacetyl-isovaline n-propyl ester on glass capillary columns coated with the chiral stationary phase N-propionyl-L-valine tert.-butylamide polysiloxane (Chirasil Val). The D-configuration of the isovaline from trichotoxin A-40 was also established independently using GC of N-pentafluoro-propionyl-isovaline (+)-3-methyl-2-butyl esters on glass capillary columns coated with OV 17.
    Materialart: Digitale Medien
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  • 20
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 248-252 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Column loadability - overload phenomenon ; Non-classical approach to theory of loadability ; Effect on retention times, peak shape ; Effect of column length ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The usual concepts of the dynamics of an overloaded solute band fail to explain several phenomena such as the typical “leading-tail” shape and retention deviations exhibited by overloaded peaks, and why these defects are more commonly observed in short columns. These and other related deviations from theory can be rationalized by a non-classical approach to the overloading phenomenon.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 21
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 286-290 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary ; Discrimination due to FID ; Effect of carrier gas flow changes on detector sensitivity ; Hydrogen as carrier gas ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The sensitivity of an FID may change when the carrier gas flow rate changes during a chromatographic run. Sample parts which are eluted at reduced FID sensitivity produce a reduced peak area, hence are discriminated as compared to other components. Sensitivity changes were studied for hydrogen as carrier gas. For the detector tested, differences in the carrier gas flow rates of 1 ml/min shifted the FID sensitivity by 1 to 5% (depending on the fuel gas supply). Thus the stability of the sensitivity is no longer ensured as soon as the carrier gas flow rate is changed manually or by an automatic programmer during an analysis. Sensitivity drifts may also occur during temperature programmed runs with a pressure regulated carrier gas supply since the gas flow through the capillary drops with increasing temperature. Such shifts in the response became noticeable as soon as relatively high carrier gas flow rates combined with long range temperature programmes were used. The typical patterns of such discriminations are shown, closing with a discussion on the possibilities for minimizing such undesired effects.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 22
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 301-302 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Polychlorinated biphenyls ; Liquid crystal phase ; Choice of stationary phases for analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
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  • 23
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 351-352 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Injector ; Concentrator ; Electrically heated inlet ; Capillary columns ; Vapor sampler ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 24
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 537-544 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Chromatographic properties of glass surfaces ; Fluorad FC 431 ; Glass capillary GC of basic compounds ; Modification of glass surfaces ; Deactivation of glass surfaces ; Acid-base behaviour of GC columns ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: “Leaching” or “etching” by strong mineral acids seems to be a necessary pretreatment step for the most commonly used deactivation procedures of glass capillaries by reaction with either polyethylene glycol or silylation reagents. The acidic sites which are formed on the surface during this acid treatment cannot be completely removed by the subsequent deactivation process. This drawback can be overcome by performing the leaching with water vapour, resulting in an accumulation of cations at the surface and a decrease in the number of silanol groups. Capillaries of this type show excellent properties for the chromatography of strongly basic compounds. After the wash-out of the alkaline surface layer, the acidity of the support is suited for the chromatography of strongly basic as well as strongly acidic compounds. Due to a lack of reactive acidic sites, special deactivation procedures have to be applied to capillaries produced in this way.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 25
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 583-584 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; (Fused silica) capillary columns ; Intermediate test ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 26
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 87-88 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, wide-bore glass WCOT ; Fourier Transform Infrared/glass capillary GC on-the-fly ; Coupling successful ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: By the use of a wide-bore WCOT capillary column, it was possible to obtain the first on-the-fly GC/FT-IR spectra with a WCOT column. This wide-bore WCOT column gave improved separation, as compared to a SCOT column, and yielded identifiable infrared spectra for a real sample.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 27
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 124-128 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Series-coupled chemically differing columns ; Fundamental studies on the properties for basic theory started ; Retention time and separation efficiency ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Basic expressions are derived for both the retention time and the effective separation factor in serially coupled GC columns. The retention time is determined by two main parameters. The first is the fractional time spent by an unretarded solute in each column which, in turn, is determined by the relative column lengths and flow velocities through each column. The second parameter is the relative mass distribution coefficient of a particular solute in each column; a variable that can be adjusted by changing the relative temperatures of the columns. The expression for the effective separation factor relates the measured separation factor for the series combination to the separation factors on the individual columns, the fractional time spent by an unretarded peak in each column, as well as the relative values of the mass distribution coefficients of a particular solute on the different columns.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 28
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; Preparation of deactivated capillaries for routine analysis ; Easy deactivation and pretreatment steps described in detail ; Comparison of different modes given ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A new surface pretreatment for the preparation of wall-coated open tubular (WCOT) glass capillary columns has been evaluated. This technique involves the application of a non-extractable layer of Superox™-4, a 4,000,000 MW polyethylene glycol, to the glass surface as a pretreatment and deactivation agent. Unlike other polyethylene glycols, Superox-4 is stable at high temperatures (〉 300°C) in the absence of oxygen, coats smoothly onto a bare glass surface and resists droplet formation. WCOT columns (SE-54, Carbowax 20M, and SP-2250) prepared using this technique are compared to columns prepared using a modified Grob [2,3] BaCO3 procedure. The Superox-4 pretreated columns were equal or superior in quality to the BaCO3 pretreated columns, based on the appearance of an activity standard and the effective theoretical plates (Neff) per meter. Chromatograms showing practical application of the WCOT columns prepared using both methods is given.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
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  • 29
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 146-146 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Cold trap heating ; Thermal focussing ; 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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  • 30
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 302-302 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary ; Fitting silica capillary columns ; 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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  • 31
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 309-310 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Amino-carboxylic acid ; Silylation ; 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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  • 32
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 299-300 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, WCOT glass ; Urea herbicides ; s-Triazines herbicides and metabolites ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The authors have shown that capillary columns are perfectly adequate for the separation of s-triazine herbicides and urea herbicides. The method presented remains adequate when the initial molecules are accompanied by some of their metabolites.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 33
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 326-332 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Column chromatography ; Run comparison with corrections for variations in injected sample sizes ; Chromatogram reconstruction on a graphics terminal ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The application of a Hewlett-Packard 3354 B Laboratory Automation System has been studied in order to compare a series of gas chromatographic analyses. A computer program has been designed for the chromatogram reconstruction of all valid sample runs from a system subsequence on an HP-2648 A graphics CRT terminal. The detector signals of the runs are compensated for variations in injected sample sizes when a number of conditions are met.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 34
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 359-360 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Mass spectrometry ; All-glass interface ; Fused silica ; 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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  • 35
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 405-410 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Determination of adsorption ; Irreversible adsorption on glass columns made visible ; Fluorescent compound PMBF2 ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: PMBF2, a pyrromethene pigment, can be used in gas chromatography. Because of its fluorescence, adsorption sites on glass columns and connections can be traced in situ. The compound can be employed to check the inertness of glass surfaces after deactivation procedures. Some applications are described.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 36
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 411-412 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; All-glass T-joints and manifolds with small dead volume, production of ; Up to five-channel outlet splitter ; 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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  • 37
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 525-526 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; Static coating ; Filling the column by pressure, not by vacuum ; Device for filling by 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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  • 38
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 528-530 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Two-phase derivatization technique ; Yeast ; Splitless injection ; 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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  • 39
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 545-550 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, fused silica columns ; Selective detectors: TSD, ECD, FPD ; POTW sludge extracts ; Effluent splitter ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Combination of various GC detectors by using a Varian effluent splitter with glass capillary columns has been found to be a rapid procedure for profiling organics extracted from sludges and river sediments. The selectivity and the increased sensitivity of the thermionic nitrogen-phosphorus detector (TSD), the electron capture detector (ECD), and the flame photometric detector (FPD) over the flame ionization detectors (FID) or mass spectrometers allow the detection of compounds present at trace levels without need for extensive sample cleanup. Furthermore, the combination of two selective detectors may supplement the information with regard to the chemical functionalities required for structure elucidation.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 40
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 551-567 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; High performance liquid chromatography ; Theoretical basis of column chromatography in multicomponent separations ; Required value of peak resolution and accuracy of obtained, quantitative method ; Plate height of solute with capacity ratio equal to one or approaching to infinity ; Linearity between peak width and retention value ; High efficient GC columns ; HPLC small-bore column ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The point of our published papers since 1957 is reviewed. The relations between the required value of peak resolution, K1 (or R), and peak separation, K3 (eqn 9); K1 and relative accuracy of a peak height quantitative method, Ph (eqn. 10); K1 and relative accuracy of a peak area method, Pa, (eqn. 12) at different concentration ratios, φ, are derived. The final result in Table 2 shows a large influence of φ on the required value of K1.The approximately linear relation between peak width and retention value (eqn. 18) exists not only in GC. but also in HPLC. Plate height values H1 and H∞ for a solute with capacity ratio, k′, equal to unity or approaching infinity, respectively, are used to evaluate the column efficiency (eqn. 20). The measuring methods (eqn. 21,22,23) and parameters effecting on H1 and H∞ are given for GC packed column (eqn. 24), GC open tubular column (eqn. 25) and HPLC (eqn. 26). In the light of this, columns of high efficiency were developed. Some typical chromatograms for high speed analysis and separation of complex mixtures are given.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
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  • 41
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 585-586 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass or fused silica ; Adsorptive and catalytic activity ; Distinction of effects ; Discussion of active sites ; 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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  • 42
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 89-90 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; Histamine TMS derivatives, complete separation, 2 minutes ; NPD used for quantitation down to 20 pg ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Complete separation of the TMS derivatives of histamine, 1-methyl histamine and 3-methyl histamine was achieved in two minutes in a 7 m × 0.25 mm column coated with SP 2250. Using NPD, histamine was detectable at levels as low as 20 pg. This offers a rapid, sensitive procedure with potential for clinical diagnosis and food analysis.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 43
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 107-114 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; Two-dimensional GC ; Odour evaluation ; Fraction collection, heart-cutting and enrichment ; Applications, essential oil analysis ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A simple but effective GC approach to odour evaluation and fraction collection with capillary columns is described. An allglass device splits the column effluent, with one splitter arm going to an FID. For odour evaluation, the other splitter arm is led via teflon tubing to the nose. Off-line heart-cutting is carried out by collecting the split effluent on a glass capillary microtrap, the inner walls of which are coated with OV-101. This allows recovery of nanogram amounts of material. Multipass operation or repeated collection leads to preparative capillary GC for further spectroscopic investigation. These techniques do not involve sophisticated equipment or valves. Applications of this type of smell analysis, heart-cutting and enrichment in the analysis of Rhododendron fragrantissimum essential oil, black pepper essential oil and hop essential oil, illustrating the versatility of the systems, are presented.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 44
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 419-420 
    ISSN: 0935-6304
    Schlagwort(e): Meprobamate ; Overdose toxicology ; Plasma monitoring ; Gas chromatography ; High-pressure liquid chromatography ; 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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  • 45
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 447-451 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; Organic gas phase cigarette smoke ; Volatile phase cigarette smoke ; Heated injection ; Nitrogen-phosphorous detector (NPD) ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A heated injection system for a microprocessor-controlled GC has been developed for the (GC)2 analysis of the volatile phase of whole smoke of a cigarette. Effects of injection port temperature and the presence of a Cambridge filter pad are demonstrated. Chromatograms are shown for smoke samples with and without a Cambridge Filter with the sample valve oven at 25°, 165° and 205°C. The use of a flame ionization and a nitrogen-phosphorous detector is illustrated.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 46
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 521-522 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Computerized gas chromatography/mass spectrometry ; Capillary, OV-73 fused silica ; On-column injection ; Alkyl porphyrins ; Bis(trimethylsiloxy)silicon(IV) derivatives ; Fused silica as a GC/MS interface ; 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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  • 47
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 568-574 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; Electron capture detection ; Analysis of carboxylic acids and phenols in water ; Extractive alkylation ; Pentafluorobenzyl derivatives ; Steam condensate and domestic sewage effluent ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A method is presented for the simultaneous determination of a wide range of carboxylic acids and phenols in water. Extractive alkylation is used with the tetrabutylammonium ion as counter ion and pentafluorobenzylbromide as alkylating agent. Extracts are analyzed by glass capillary gas chromatography and electron capture detection. Using one ml of water sample, the detection limit lies in the range of 1-10 μg/l. Application has been made to the analysis of steam condensate and domestic sewage effluent.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 48
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 196-196 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; Persilylation ; Barbiturates ; 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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  • 49
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 461-470 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Series-coupled columns equipped with different stationary phases ; Independent temperature control of columns ; Retention time expressions ; Theory ; Selectivity control ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The promising technique of controlling chromatographic selectivity by the adjustment of individual column temperatures in systems of series-coupled columns is investigated by means of a general model incorporating the effects of temperature and mobile phase compressibility. Expressions are derived for the linear flow velocity, the effective partition coefficient and the retention time for a system of n columns assuming an ideal mobile phase gas, under conditions of constant overall pressure drop and neglect of the temperature dependence of the mobile phase viscosity. The results indicate the importance of thermodynamic parameters, relative to parameters influencing the linear flow velocity, in determining the effect of temperature on the chromatographic retention time. Numerical results are illustrated graphically for two-column systems which are discussed in greater detail. Switching of columns is also discussed and it is shown that even if thermodynamic contributions remain unchanged, non-thermodynamic contributions have a notice-able effect.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
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  • 50
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 21-22 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; Deactivation ; Dynamic vapour-phase silylation ; 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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  • 51
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 86-86 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Recycle chromatography ; Multiple-pass chromatography ; Thermal focussing ; 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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  • 52
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 195-195 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Columns, packed ; High resolution ; Packing apparatus ; 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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  • 53
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 298-298 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; Closing technique for static coating ; 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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  • 54
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 333-336 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Liquid crystal ; N,Ń, Bis (p-phenylbenzylidene)-α, α′-bi-p-toluidine (BPhBT) ; Steroids ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A gas-chromatographic separation of underivatized steroids is described, in which the liquid crystal N,Ń-bis(p-phenylbenzylidene)α,α′-bi-p-toluidine (BPhBT) was used isothermally at 265°C for the stationary phase. The nematic range of this crystal is 247 to 403°C. Use of the BPhBT crystal allowed operations in a temperature range where steroids are volatile and unlikely to display broad elution peaks and long retention times.With columns precoated with 2.5 weight percent of BPhBT, steroids containing minor structural differences in the ring system were readily differentiated. For example, 5-androsten-17α-ethinyl-3β, 17β-diol was found to elute more rapidly than its 3-keto analog, ethisterone. Ethisterone was distinguished readily also from its 19-nor analog, norethisterone. Additionally, differences in side-chain functionality and resultant molecular dimensions facilitated the separation of steroids of identical ring structure, as in the comparison of cholesterol with methyl 3β-hydroxy-5-cholenate and 25-hydroxycholesterol.An enhancement of separation according to the molecular length-to-breadth ratio was observed; in general, the larger this length-to-breadth ratio, the greater the retention period on the column.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 55
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 357-358 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary column, glass ; Interface, home-made ; Headspace analysis ; 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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  • 56
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 307-308 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Volatile polymers ; Polyethylene glycols ; Comparison between CPG and ofter methods ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 57
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 352-354 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Short capillary columns ; Rapid analysis ; Polycyclic aromatic hydrocarbons ; 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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  • 58
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 471-472 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, fused silica ; Element-selective MED ; Organometallics ; 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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  • 59
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 627-633 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Vaporizing injectors ; Dicrimination of high-boiling components ; Elution out of the syringe needle ; “Hot needle”, “solvent flush” techniques ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Unequal elution of sample components of different volatility out of the syringe needle is one of the major causes for discrimination occuring during the injection, i.e. the phenomena which results in peak areas for the high boiling compounds which are too small compared with the volatiles. This problem, associated with all vaporizing injectors that are used with syringes, can be minimized by careful choice of the needle handling technique. Various methods are compared experimentally. The “solvent flush” method is discussed in detail and demonstrated to be ineffective for reducing losses in the syringe needle. The “hot needle” technique, where the empty needle is preheated in the injector before pushing the plunger, was found to be superior or equal to an improved “solvent flush” method (which included preheating the needle and omitting the air plug between sample and flushing solvent. Generally it was found that the discrimination due to the syringe needle was reduced for larger sample volumes, although no further changes were noticed when these exceeded 2.5 to 3μl.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 60
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 641-642 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; Polar open-tubular columns ; Silar 10CP, 0.2% ; Recoating of capillary columns to restore efficiency ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 61
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 23-24 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass or metal ; Connecting cement ; Silver chloride ; Heat-stable to 400°C ; 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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  • 62
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 169-171 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Glass capillary columns ; Trimethylsilyl derivatives ; Pregnant mares' urine estrogens ; Estrone-equilin separation ; OV-225, Silar 10C stationary phases ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Glass capillary columns coated with OV-225 and Silar 10C were used to analyze estrogens (as their trimethylsilyl derivatives) present in pregnant mares' urine. Such columns provide better resolution in a shorter time than the corresponding packed columns, as exemplified by the separation of estrone from equilin.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 63
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 493-496 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; Persilylation procedure ; Discussion of experimental parameters ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Persilylated glass capillary columns are the most universal GC columns available. They are relatively easy to prepare, but there is nevertheless a great need for helpful practical instructions. In the recent literature, methods and conditions for the preparation of persilylated columns have been recommended, but these might confuse the individual column maker, since they seem to originate from limited observations rather than from comprehensive investigation. They will hardly help to make column preparation safer. This paper attempts a summarized view of the present experience with persilylation and provides basic information for column makers.
    Materialart: Digitale Medien
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  • 64
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 523-524 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Precoating capillary columns ; Aromatic amines ; 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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  • 65
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 527-528 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; Surface deactivation ; High temperature silylation ; Cyclic trifluoropropylsiloxanes ; Improved surface wettability ; 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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  • 66
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 25-27 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Instrumental modification to multidimensional separation ; Application with packed columns on complex sample composition ; Indene to pyrene range in coal tar ; 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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  • 67
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 35-36 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; Enantiomer separation ; Chiral stationary phase ; D.L. proline and D. L. secondary amines ; 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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  • 68
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 91-91 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; Static coating technique details ; End-sealing without failure, under ethanol ; 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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  • 69
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 129-132 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Quantitative determination of the drug derivative in 1 ml biological fluid ; 10 ng/ml level ; Standard curve ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 1-(o-methoxyphenoxy)-3-isopropylamino-2-propanol hydrochloride (moprolol, OmeralR), is a new β-adrenergic blocking agent. A gas chromatographic method for determining unchanged moprolol in human biological fluids has been developed. After solvent extraction, a bis-trifluoroacetyl derivative was formed and measured by an electron capture detector. The quantification was checked by using an internal standard (pronethalol), which was added to all samples. The electron capture response was linear between 10 and 500 ng/ml. To avoid contamination of the peaks, careful extraction was imperative. The main advantages offered by the described method are: specificity, high sensitivity (10 ng.ml-1) and the small amount of biological fluids (1 ml plasma a. e.) required.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 70
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 166-168 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Packed columns ; Single compounds of special interest accurately analysed in multicompound mixtures ; Separation efficiency in MDSS separation multiplied, therefore often comparable to capillary GC separation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Methanol, 2-Me-propanol-2, propanol-2, benzene, toluene and xylenes in gasoline blends were determined using a valveless multi-dimensional switching system (MDSS) with two packed columns and temperature programming.Compounds of interest, interfering with paraffins and naphthenes, were in a sequence of four heart cuts transferred onto the second column. The resulting baseline separation enabled precise quantitative measurement within a short analysis time. Instrument settings, times of switching and integration parameters were stored in an instrument memory file (user table) and thus high precision in the measurements was achieved.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 71
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 197-198 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; Introducing phenyl groups by persilylation ; Dependence of wettability on density of phenyl groups ; Practical instructions ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 72
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 241-247 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; Quantitative analysis at 10-10g level ; Steroids in urine ; Amino acid fluorobutyrates (19 in 35 min) ; Installation of glass capillaries ; Connection to FM-ECD ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Glass capillary columns are ideal for analysis of urinary steroid profiles (i.e. the total steroid neutral fraction without prior separation into sub-groups).In this paper performance of both SCOT and wide-bore WCOT columns has been compared, resulting in no significant quantitative difference on urine extracts run as trimethylsilyl ether derivatives. However, because of increased efficiency the WB-WCOT column exhibited more sensitivity in measurement of small amounts of 11-ox-aetiocholanolone. Sensitivity of other steroids was greatly enhanced by use of either SCOT or WB-WCOT, leading to an almost tenfold increase over conventional packed columns (e.g. androsterone and aetiocholanolone 〈 40 μg per 24 h urine sample). A simple splitless injection system (based on a design of Dr. W. Greenaway, Oxford University) is presented.Experiments were also carried out using a SCOT column in conjunction with an FM-electron capture detector. Whilst efficiency was impaired due to the design of the detector, use of He (carrier) and N2 (make up gas) showed that several steroid derivatives could be easily measured at well below the 10-10 g level with much more rapid retention times than with a 1½m packed column. Highly successful separation of 19 amino acids (as fluoro-acyl derivatives) was achieved in 35 minutes using a SCOT (30 m) SP2100 column.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
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  • 73
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 303-305 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary columns ; Surface modification ; Sulfur dioxide treatment ; 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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  • 74
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 311-312 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Fused silica capillaries ; Free amines ; Humidity of carrier gas ; 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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  • 75
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 648-650 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; N-P detector ; Sequential simplex optimization ; 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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  • 76
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 473-474 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography ; Capillary, glass ; Complex wax ester mixtures ; Resolution of components by total carbon number and by degree of unsaturation ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A glass capillary GC method providing high resolution analysis of complex wax ester mixtures is described. The two key parameters needed for evaluating a wax ester mixture for industrial utility - the total carbon chain length and the number of carbon-carbon double bonds present in each component - are simply and rapidly obtained by this method.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 77
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 18 (1980), S. 1125-1136 
    ISSN: 0098-1273
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Dielectric relaxation of polyacrylonitrile (PAN) samples, in which the presence of an amorphous phase is evidenced by x-ray diffraction, has been studied over the temperature range 30-150°C and frequency range 102-105 Hz. These data as well as those reported by other authors, reveal several points useful to the understanding of the dielectric relaxations of PAN in relation to its structure. A glass transition in PAN is evidenced by at least two of the four data sets investigated; the third shows combined effect of two relaxations, whereas the fourth clearly shows a relaxation process different from the glass transition. The glass-transition behavior of the dielectric relaxation data is confirmed by Williams-Landel-Ferry theory and a recent theory of Phillips, both of which lead to consistent conclusions.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 78
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 18 (1980), S. 1175-1186 
    ISSN: 0098-1273
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The flexibility of some polyimide chains has been studied theoretically as a function of the chemical structure of the repeat unit. It has been shown that the thermodynamic flexibility can be varied over a wide range by the choice of the unit structure. For three polyimides, as an example, the flexibility of cyclochain structures approximates that for free rotation.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 79
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 18 (1980), S. 1237-1242 
    ISSN: 0098-1273
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Electron microscopy reveals a high-temperature morphological transition in a styrene-butadiene-styrene block copolymer of 7000 polystyrene block molecular weight and 43,000 polybutadiene block molecular weight (7S-43B-7S). Samples quenched in liquid nitrogen from temperatures above 150°C show no structure, whereas those quenched from temperatures below 140°C clearly show a multiphase structure. We previously reported that the 7S-43B-7S polymer exhibits a relatively sharp melt rheological transition in the temperature region between 140 and 150°C from highly viscoelastic and nonlinear viscous behavior to linear viscous behavior with insignificant elasticity. The dynamic viscoelastic properties are measured at different strain amplitudes in this study, and the results show that the melt rheological transition behavior is not influenced by the strain amplitude. This study clearly shows that the melt rheological transition in the 7S-43B-7S results from a morphological transition from a multiphase structure below about 140°C to a single-phase structure above about 150°C.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 80
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 18 (1980), S. 1103-1124 
    ISSN: 0098-1273
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: A model of simple molecule sorption in polymers is proposed which embraces both the glassy and rubbery regions, and incorporates the successful dual-mode model below the glass-transition temperature. Hole filling is shown to be an important sorption mechanism both above and below Tg, although saturation effects do not occur in the rubbery polymer. The model interprets the “dual-mode” Langmuir and Henry's law parameters at the molecular level, and a simple statistical mechanical analysis allows estimation of the parameter values, as well as specifying certain interrelationships between the parameters. Applications of the model to gas solubility data in five polymers are considered [polyethylene (PE), poly(ethylene terephthalate) (PET), polystyrene (PS), polymethacrylate (PMA), poly(vinyl acetate) (PVAc)] and semiquantitative agreement is obtained for PE, PET, and to a lesser extent, PS. For PMA and PVAc, the agreement is qualitative only.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
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  • 81
    ISSN: 0098-1273
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Wide-angle x-ray relaxation studies were performed on films of low- and high-density polyethylene (PE). The samples were rapidly stretched by a pneumatic stretcher and held at a fixed length. The rate of crystal reorientation was monitored by measuring diffracted intensity changes using a count-rate meter with output displayed on a storage oscilloscope as well as a digital counter-timer. Experiments were completed at several temperatures and activation energies comparable to those reported for the α1 relaxation in PE were obtained.
    Zusätzliches Material: 18 Ill.
    Materialart: Digitale Medien
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  • 82
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2129-2142 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Homogeneous catalytic systems based on optically active low-molecular-weight and macromolecular titanium alcoholates and tri-isobutyl aluminum were used in the isomerization and hydrogenation of chiral and prochiral olefins. The reactions performed in a nitrogen and hydrogen atmosphere show a different behavior in regard to reaction rate, composition of reaction mixture, and stereochemical control. The catalyst based on macromolecular titanium alcoholate displays lower activity and a varying influence on the stereochemical pathway with respect to the catalysts based on low- molecular-weight alcoholates. The data obtained in both cases strongly support the absence of a stereocontrol by the growing chain in the stereoelective polymerization of racemic α-olefins by Ziegler-Natta catalysts based on optically active precursors. Finally evidence is provided in favor of the intermediate step responsible for asymmetric isomerization which does not occur via η-allyl complex.
    Zusätzliches Material: 5 Tab.
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  • 83
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2461-2470 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A general detailed model of polymer oxidative degradation in the presence of a stabilizer-oxygen acceptor was considered. The motion of the degradation zone boundary and the sample lifetime were obtained for various conditions of the process. In particular, it is shown that within the given concentration immobile oxygen acceptor has the best stabilizing properties. The theoretical results are compared with the experimental data obtained by using two independent methods: polymer sample cracking and a change in the ESR signal. Good agreement between theory and experiment was obtained.
    Zusätzliches Material: 6 Ill.
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  • 84
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2197-2207 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Radical polymerization and copolymerization of some o-alkylphenyl methacrylates were carried out and the effect of the ortho-substituents on the ability to homopolymerize, on the monomer reactivities, and on the ceiling temperatures of the monomers was studied. The effect of the substituent on tacticities and thermal stabilities of the polymers formed was also discussed. The ability to honiopolymerize and the monomer reactivity were considerably decreased by the introduction of the o-substituent. 2,6-Di-tert-butylphenyl methacrylate formed no methanol-insoluble polymer at 60°C. On the basis of the tacticity determined it was noted that the o-substituted phenyl methacrylates preferred syndiotactic addition in the propagation reaction less than did phenyl methacrylate or methyl methacrylate. The polymers formed from the o-substituted monomers were thermally less stable than poly(phenyl methacrylate), and, consistent with this finding, ceiling temperatures of the o-substituted phenyl methacrylates seemed to be lower than that of phenyl methacrylate. The effects observed were characteristic of the o-substituents conformationally close to the carbon-carbon double bond of the monomer or the carbon carrying the unpaired electron of the polymer radical.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 85
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2239-2246 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The copolymerization of acrylonitrile (r1) and p-acetoxystyrene (r2) in bulk yields reactivity ratios r1 = 0.08 and r2 = 0.42. Crosslinked resins are readily obtained by a new type of precipitation copolymerization of acrylonitrile, p-acetoxystyrene, and divinylbenzene. After deacetylation, the phenolic groups afford useful attachment sites for protected amino acids as a first stage in solid-phase peptide synthesis. Reactivity of typical 10% functionalized polyacrylonitrile-based resins is comparable to that of the more usual polystyrene-based equivalents, although swelling characteristics of the two types of resin are very different.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 86
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2281-2291 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The Macosko-Miller approach is used to obtain an expression for the polydispersity index for AA, BB, CC linear step polymerization system in which B and C are the same type of functional group. The dependence of the polydispersity index, as a function of the extent of reaction, on the monomer masses and on the relative reactivities of B and C groups toward A, is examined in detail.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 87
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2307-2322 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The various kinds of molecular defect that are related to the thermal property of polyacrylonitrile (PAN) are studied in detail in relation to the polymerization mechanism in an aqueous medium. The existence of two different kinds of polymer radical is pointed out and the significance of polarity of radical species is emphasized. It is shown that the structural irregularity along the main chain is surely present but has little effect on the thermal property of PAN. It is estimated that one of the most significant defects relating to the thermal property is the main-chian type of branching the occurs predominantly in hydrogen on a polymer backbone. The relationship between activator (i.e., NaHSO3) incorporation and branch inhibition mechanisms is discussed. The optimum polymerization condition, under which the highest thermal quality of molecules is obtained, is found empirically within a limited experimental range, for an aqueous heterogeneous system.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
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  • 88
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2333-2346 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reaction of chloromethylated polystyrene with methyl(2- hydroxyethyl)amine and butyle (2-hydroxyethyl)amine was studied kinetically. The reaction of benzyl chloride with these amines was also investigated for comparison. N,N-dimethylformamide and dioxane were used as solvents. The reactions of benzyl chloride with the two amines in these solvents took place according to normal kinetics of the second order. Reaction kinetics depend on the nature of the amine and solvent in Chloromethylated polystyrene reactions. In dioxane the self-accelerating effect of the reaction for β ≃ 0.5 is apparent. Steric hindrance of the reaction, beginning with a conversion degree of about 75%, wss observed for butyl(2-hydroxyethyl)amine in N,N-dimethylformamide. This self-accelerating effect is observed in dioxane at the same reaction degree. The activation energies and frequency factors were calculated for the amination of benzyl chloride and chloromethylated polystyrene with the two amines in N,N-dimethylformamide and dioxane.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 89
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2391-2410 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 2-Methyl-5-vinylpyridine-N-oxide, 4-vinylquinoline-N-oxide. 9-vinylacridine-N-oxide, p-N,N-dimethylaminostyrene-N-oxide units were introduced in polymeric chains as homopolymers or/and as styrene copolymers to study their photocrosslinking. The method used for characterization of photocrosslinked films was a “photoresist test” described in Part I of this series. The photosensitivity of the different chromophores bound to the different polymer has also been studied by UV, IR, and fluorescence spectrophotometries. The use of aromatic amine N-oxide groups in polymers seems to be a general means to produce their photocrosslinking by radical reactions. Among the different polymeric materials prepared, 4-vinylpyridine-N-oxide and 4-vinylquinoline-N-oxide are the most photosensitive.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
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  • 90
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2437-2449 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Polymorphic behavior and γ-ray-initiated postpolymerization of the even-numbered long-chain Methacrylates (C18-C12) have been investigated. Phase transition behaviors of octadecyl, hexadecyl, tetradecyl, and dodecyl methacrylates are respectively, which become simpler with shortening of the chain length. The methacrylate monomers with sufficiently long hydrocarbon chains, such as octadecyl and hexadecyl, can be polymerized rapidly in the α-form crystal (hexagonal packing) by a fully two-dimensional mechanism, whereas in the β-form crystal (triclinic packing), polymerization can hardly occur. In the case of dodecyl methacrylate, however, an accelerated polymerization in the β form occurs after an induction period of several hours and the resultant polymer is gel-like. This can be interpreted by the propagation reaction across the polymer chain already formed. It has been found that the solid-state post-polymerization of n-alkyl methacrylates is affected by the chain length through the packing mode of the monomer molecules and also by the aggregation state of side chains in the resultant comblike polymer.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 91
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The effect of epoxy groups at the surface layer of ethyl acrylate-glycidyl methacrylate copolymer (1) emulsion particles on its crosslinking reactivity has been investigated. For this purpose two series of I emulsions were prepared. In the Y series, of which emulsion particles have epoxy groups at the surface layer, the epoxy content in the polymerization recipe was varied. For preparing the X series, of which emulsion particles have few epoxy groups at the surface layer, the high epoxy content of a given emulsion was reduced by various degrees of cleavage reaction with HCl-CaCl2. In emulsion blend films with amine-group-containing copolymer (II) emulsion, where the crosslinking reaction was expected to proceed only at the interfacial layer of I and II emulsion particles, the Y series, compared to the X series at the equal overall epoxy content in particles, showed less swelling and higher gel fraction in dioxane, less swelling in water, and higher tensile strength and modulus. On the other hand, this difference was not observed in the next two crosslinked films in which crosslinking was expected to be homogeneous. First, blends of I and II, which were isolated from the corresponding emulsions discussed above, were cast from dioxane solutions. Second, I emulsions were cast with BF3 ether complex which was expected to penetrate into the particles. It is concluded that the response of I emulsion cleaving the epoxy groups at the surface layer of particles to subsequent interfacial crosslinking is obviously reduced. However, even such an emulsion can be crosslinked to an extent similar to that of an uncleaved emulsion with similar overall epoxy content, if the crosslinking reaction is conducted so as to give an homogeneous effect.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 92
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Ammonia used as both reactant and solvent has been shown to dehydrochlorinate 1,1,1-tri-chloro-2,2-bis(4-hydroxyphenyl)ethane smoothly to 1,1-dichloro-2,2-bis(4-hydroxyphenyl)ethylene. The reaction is complete in 1 hr at 100°C, and after two crystallizations from methanol/water affords polymerizable quality monomer for the synthesis of highly flame-resistant polycarbonates. The use of organic solvents in combination with ammonia does not offer any rate advantages over pure ammonia. Primary and secondary amines also can be used to effect the dehydrochlorination but, except for the methylamine, are significantly less reactive and lead to less pure product than amonia.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 93
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2513-2521 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reaction of p-benzoquinone with tin tetrachloride in the absence of solvents was investigated by isolation and identification of the reaction products. This reaction leads to the formation of polymeric quinone-tin derivatives free from combined chlorine, chlorinated quinones, quinhydrone, and minute amounts of CI2 and HCI gases. The tin content varies accroding to the molar ratios of the reactants and reaches its maximum (72%) at the smallest SnCI4 ratio. The existence of the Sn-Sn bond in the polymeric derivatives was confirmed chemically and spectroscopically. A mechanism based on the formation of radical intermediates which can account for the reaction products was developed. In view of their quinonoid nature, high thermal stability, and the presence of Sn-Sn bonds, the polytin derivatives are to be investigated as radical traps in the stabilization of polymeric arcticles against radical degradation process.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 94
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2523-2533 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The polymeric p-benzoquinone-tin derivatives obtained from the reaction of p-benzoquinone with tin tetrachloride in the absence of solvent have been investigated as thermal stabilizers for rigid PVC at 200°C by measuring the rate of dehydrochlorination. The results reveal the greater stabilizing efficiency of the investigated products in relation to dibutyltin maleate and the basic lead stabilizers commonly used in industry. Evidence has been accumulated that the quinone and metallic elements (Sn—Sn bonds) of the stabilizer participate in the stabilization process by trapping the radical intermediates of degradation and blocking the odd electron sites formed on the polymer chains. Although stabilizers with high quinone content provide greater stabilization in the early stages of degradation, their efficiency sharply decreases in subsequent stages. On the other hand, stabilizers of high tin content effectively prohibit the dehydrochlorination reaction at all stages of degradation. On an equivalent basis of metal content, the results clearly demonstrate the greater stabilizing efficiency of tin atoms when found in direct contact in the stabilizer molecule. The mechanism of stabilization suggested to account for the results obtained may be considered as additional evidence in support of the radical nature of the dehydrochlorination reaction.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 95
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2577-2583 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Availabilities of O(3)H relative to O(2)H (that is, [O(3)H]a/[O(2)H]a) on accessible surfaces of microstructural units of cotton fibers were measured by chemical microstructural analysis (CMA). CMA involves a mild chemical reaction with N,N-diethylaziridinium chloride, determination of substituent distribution for this product and a corresponding product from decrystallized cellulose, and simple computations. Measurements for fibers in commercial cotton fabric, for field-dried fibers, and for never-dried fibers are reported. The [O(3)H]a/[O(2)H]a, an inverse measure of intact O(3)H ·· O(5′) bonds, decreased in the stated order; thus, intact O(3)H ·· O(5′) hydrogen bonding increased in this same order. Results indicate a high degree of order in intramolecular bonding in the never-dried fiber and an increasing disruption of this bonding as the never-dried fiber is dried and processed.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 96
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2597-2608 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Mixtures in various proportions of natural rubber (NR) and each of two tackifier resins, a poly-β-pinene and a modified pentaerythritol rosin ester, were used as the adhesive layer in joining a flexible polyester strip to a plane glass substrate. Measurements of the force required to peel the strip from the glass at a 90° angle were made over a range of pulling rates at several temperatures. Application of time-temperature superposition enabled a master curve of (reduced) peel force versus (log) pulling rate at a standard temperature (296 K) to be obtained for each adhesive composition. The master curves showed, in increasing order of pulling rate, some or all of four different modes of peeling: (i) peeling with viscous adhesive response, (ii) peeling with rubbery response, (iii) oscillatory or slip-stick peeling, and (iv) peeling with glassy adhesive response. In general, transitions between the different peeling modes were quite abrupt. Increase in concentration of tackifier resin caused displacement of the master curve toward lower pulling rates [an effect interpreted in terms of an increasing adhesive glass temperature (Tg)], and a superimposed displacement of the transition between peeling modes (i) and (ii) toward higher pulling rates-an effect attributed to reduction in adhesive average molecular weight. The influence of the tackifier resin in modifying the viscoelastic characteristics of the adhesive was further demonstrated in a comparison of the peel force master curves with corresponding master curves of dynamic storage modulus.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 97
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2641-2648 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Phase diagrams for monomer (methyl acrylate containing microemulsions) are shown and described. Polymerizations of a series of microemulsified monomer reveals the expected linear dependence of 1/DS vs. [S]/[M] for pentanol acting as a chain transfer agent and giving a value of 5.1 × 10-4 for Cs. No break in molecular weight behavior was shown as a result of micellization at higher water contents. A comparison of molecular weights obtained by various classical methods (solution, emulsion, bulk) are also given.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 98
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2663-2676 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Soluble tricarbonylchromium complexes were made by reacting Cr(CO)6 with a ladder polyphenylsilsesquioxane and a linear polydiphenylsiloxane. These new polymer Cr(CO)3 complexes were characterized by elemental Cr, infrared (IR), gel permeation chromatography (GPC), viscosity, and thermal analyses and were evaluated as stereoselective hydrogenation catalysts. Thermogravimetry studies demonstrated that the new complexes were more stable at 180-200°C in N2 than the corresponding complex from crosslinked polystyrene. These silicone polymer complexes catalyzed stereoselective hydrogenation of methyl sorbate to cis-3-hexenoate in cyclohexane and tetrahydrofuran (THF) and could be recovered from THF for recycling by precipitation-fiItration. Catalytic activity and recyclability, however, were highly influenced by the solvent. Loss of catalytic activity associated with loss of Cr(CO)3 was observed on recycling. These results support a mechanisim that involves dissociation of Cr(CO)3, a significant portion of which cannot become reassociated with the polymer phenyl groups.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 99
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2723-2729 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A mild, efficient method of nitrating olefins was described recently by Corey and Estreicher. Application of their procedure to diene polymers failed because of the insolubility of the hydrophobic polymer in the aqueous nitromercuration regent. Use of water-immiscible organic cosolvents gave slow nitromercuration with substantial formation of nitrite esters. To overcome these problems a nonaqueous phase transfer-assisted method of rapid selective nitromercuration of diene polymers was developed.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 18 (1980), S. 2737-2746 
    ISSN: 0360-6376
    Schlagwort(e): Physics ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Blends of polystyrene and poly(2,6-dimethyl-1,4-phenylene oxide) that cover the entire compositional range have been subjected to the action of singlet oxygen from microwave discharge, dye-sensitized reaction, and photochemical oxidation. With the applied analytical technique, which consisted of infrared (IR) analysis, including ATR technique and a spectroscopic method combined with chemical analysis for hydroperoxide groups, it was not possible to detect any effect of the singlet oxygen treatment. For that reason singlet oxygen does not appear to be important to the initiation of the photooxidation of these blends. In connection with photochemical oxidation the interaction observed between the two components probably involves energy transfer from PS to PPO. This interaction results in the enhancement of reactions in PPO that lead to greater carbonyl group formation and crosslinking. Simultaneously, the probability of chain scission in the PS is lowered with increased PPO content, found by determining the changes in the molecular weights.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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