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  • 1
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    Unknown
    Berlin : Periodicals Archive Online (PAO)
    Orientalistische Literaturzeitung. 70:1 (1975:Jan./Feb.) 75 
    ISSN: 0030-5383
    Topics: Linguistics and Literary Studies , Ethnic Sciences , History
    Notes: Besprechungen
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 10 (1977), S. 580-587 
    ISSN: 1612-1112
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An introductory discussion is given on the manufacture of glass capillary columns, including details of the methods of column testing and of the properties of the inner surfaces of glass capillaries. As a result a simple method for the testing of various kinds of support surfaces is presented which allows stepwise control of the column making procedure. A new kind of pretreatment of soft glass surfaces with HCl and HF at 450°C is described which allows the production of non-polar columns with much improved tailing behaviour for strongly polar solutes. Concerning capillary column sampling a new technique of “direct” sampling without previous vaporisation of the sample outside the column is presented together with a double column system for “selective” sampling of complex mixtures.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 8 (1975), S. 517-530 
    ISSN: 1612-1112
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary After a general introduction on the advantages and special requirements of gas chromatography in glass capillaries the methods of preparing and testing thin film capillaries are described to an extent not convered in the authors' previous paper. By means of a series of chromatograms of typical artificial and genuine samples it is shown that the use of glass capillaries of variable length and with various stationary liquids does not present technical or methodical difficulties. With regard to temperature stability there is no difference in performance between packed and glass capillary columns. Moreover the preparation of glass capillary columns is easy, their separation efficiency is much better and the tailing behaviour is often superior in comparison with packed columns.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1612-1112
    Keywords: Glass capilary GC ; Heat resistant surface deactivation ; Testmixtures ; Polycyclic aromatic hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A new method of making alkylpolysiloxane (OV 1, OV 101, OV 17, Dexsil 400, SE 52, SE 54) columns with high stability at temperatures above 300°C of both the stationary liquid itself (low bleeding) and of the surface deactivation (no tailing of polar solutes with extended use at temperatures beyond 250°C) is described. The best results were achieved on dealkalinized alkali glass but also on borosilicate surfaces which have been additionally HF treated before coating in both cases. The procedure can also be applied to leached alkali and borosilicate surfaces successfully. The best deactivations of the glass surface are attained in a two step procedure: firstly by treatment with gaseous HF/N2 mixture and secondly by simple heating of the coated and closed column at temperatures between 350° and 450°C for several hours. The tailing behaviour of such columns for polar solutes is considerably improved by this procedure as shown by test chromatograms. The procedure can also be applied to leached alkali and borosilicate surfaces successfully.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1612-1112
    Keywords: Alkylpolysiloxanes ; Capillary columns ; Fused silica ; Soft glass ; Crosslinking by γ-radiation and peroxid treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Crosslinking of alkylpolysiloxane stationary phases, especially in thick film capillary columns, is useful for the homogenous coating of fused silica and pretreated alkaliglass surfaces. The films of the stationary liquid are immobilized against solvent rinsing using CH2Cl2, pentane, and acetone, and maintain homogenity even at high temperature. Various doses of γ-radiation from a60Co. source were used for the crosslinking instead of the thermal peroxid treatment recently described by other authors. The effect of the γ-radiation crosslinking-procedure was investigated in comparison to the peroxid method in regard of: decrease of stationary phase content by solvent rinsing, separation efficiency, tailing behaviour, and bleeding of the columns obtained. Similar results as with the cumylperoxid-treatment were achieved using the γ-radiation-method. By γ-radiation no polar functional groups or moleculs are introduced into the stationary phase, however, as with the peroxid method. Less than 20% of the various stationary liquids are usually removed from the columns by solvent rising after crosslinking using both methods depending on the doses of radiation and the cumylperoxid concentration applied respectively.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1612-1112
    Keywords: On-line hydrogenation ; Platinum, palladium catalysts ; Fused silica capillary reactor ; Double oven chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A special coupling piece for the connection of fused silica or softglass capillary hydrogenation reactors with capillary separation columns using a double oven GC instrument is described. The temperatures of reactor and column can be independently adjusted thereby. This system for on-line hydrogenation also includes two injectors to be used either before the reactor or before the column and a device for trapping the hydrogenated material inside the column. Platinum and palladium catalysts of various activities were investigated, aromatic hydrocarbons and compounds containing polar functional groups can be hydrogenated easily.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1612-1112
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1612-1112
    Keywords: Glass capillary GC ; Fused silica ; Pretreated alkali glass ; Deactivation PSD polysiloxane degradation ; Polar solutes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The method of support surface deactivation by PSD (alkylpolysiloxane degradation) at temperature between 300 and 450°C previously described was used to deactivate both fused silica and alkali glass surfaces of capillary columns. The latter surfaces had to be pretreated before deactivation with aqueous HCl leaching or by the “dealkalisation” method using flowing HCl gas at 450°C and subsequent rinsing with water for alkali removal. Excellent alkylpolysiloxane columns with regard to tailing and irreversible adsorption of highly polar solutes have been obtained on both fused silica and the pretreated alkali glass. Fused silica does not require pretreatment before deactivation by the PSD-method, however. Good polyethyleneglycol (Carbowax 20 M) columns can also be obtained by coating the two types of surfaces when no deactivation is necessary. Deactivation by the PSD method cannot be applied in this case because polar stationary liquids do not adhere to alkylpolysiloxane deactivated surfaces. Sample capacity problems arising when separating highly polar solutes with non-polar stationary phases have also been investigated.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Trimethylsulfonium hydroxide (TMSH) ; FAME analysis ; Bacteria ; Blood serum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Trimethylsulfonium hydroxide (TMSH) can convert fatty acids into the corresponding fatty acid methyl esters (FAMEs) in a single step. These fatty acids may also be bound in biomolecules such as phospholipids and/or glycerides. Complex mixtures of saturated and unsaturated FAMEs which may contain hydroxy and cylopropyl groups are obtained by trans-esterification; they can easily be separated in most cases by capillary GC. When FAMEs are generated from different microorganisms e.g. bacteria the patterns of the chromatograms are characteristic. Examples of characteristic patterns of bacteria with different cell wall structures are shown. The described method of transesterification can also be applied directly to blood serum without sophisticated sample pretreatment. The profiles of the chromatograms match well those described in the literature obtained by other methods of trans-esterification or sample preparation.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 3 (1980), S. 206-207 
    ISSN: 0935-6304
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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