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  • Analytical Chemistry and Spectroscopy  (8)
  • Carbon disulfide  (2)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Monatshefte für Chemie 128 (1997), S. 881-891 
    ISSN: 1434-4475
    Schlagwort(e): 2-Methoxymethylpyrrolidine ; Carbon disulfide ; Pyrrolidine-1-dithiocarboxylates ; Crystal structure ; Diastereomers ; HPLC
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Formation of the 2-methoxymethyl-pyrrolidine-1-dithiocarboxylates2–4 and alkylation of2 and3 were studied. Enantiomeric and diastereomeric derivatives of4, the preparation of diastereomeric mixtures of4 by alkylation of3 in the presence of strong bases, and formation of6 by phase transfer alkylation of2 are described. The two enantiomers of 2-(4-bromophenyl)-2-oxo-ethyl 2-methoxymethylpyrrolidine-1-dithiocarboxylate2 have been characterized by X-ray analysis.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 12 (1989), S. 49-50 
    ISSN: 0935-6304
    Schlagwort(e): Coupled LC-GC ; Olive oil ; Erythrodiol ; 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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  • 3
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 12 (1989), S. 89-95 
    ISSN: 0935-6304
    Schlagwort(e): Gas chromatography, GC ; Injector design ; Splitless injection ; Injector overflow ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Injector overflow is determined quantitatively by analysis of the septum purge effluent. Vaporizing chambers must have an internal volume of about 1 ml (e.g. 80 × 3.6 mm i.d.). This allows splitless injection of volumes between 1 and 2.5 μl, depending on the solvent. The septum purge should be closed during splitless transfer to prevent losses by back-diffusion.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 12 (1989), S. 591-598 
    ISSN: 0935-6304
    Schlagwort(e): On-line coupled LC-GC ; Partially concurrent eluent evaporation ; Early vapor exit ; Retaining pre-column ; Irradiated fat ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: This paper reports two subjects. It describes LC-GC transfer by partially concurrent eluent evaporation at a greatly accelerated rate, as required for optimal compatibility with 2-3 mm i.d. LC columns and LC flow rates up to some 500 μl/min. Evaporation rates around 200 μl/min were obtained using a 0.53 mm. i.d. uncoated pre-column and an early vapor exit. A stationary-phasecoated “retaining” pre-column was used for preventing escape of volatile solutes through the vapor exit.The technique was used for the detection of food irradiation by analyzing selected radiolysis products of triglycerides, namely alkanes/alkanes and aldehydes. Extracted fat of chicken, hazel-nuts, and soup mixes was injected in LO and the relevant fractions were transferred on-line to GC. For chicken and nuts, detection of irradiation was possible down to doses below 0.5 kGy. Detection limits were higher for soup mixes due to interfering peaks.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 14 (1991), S. 33-39 
    ISSN: 0935-6304
    Schlagwort(e): Coupled LC-GC ; Group-type analysis ; Mineral oil ; Batching oil (jute) ; Food contamination by hydrocarbons ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Aromatics of a C15—C30 mineral oil fraction, the “batching oil” used for producing jute fabrics, were analyzed for estimating the toxicity of oil transferred from jute bags to foods. Group-type pre-separation according to ring systems occurred on a LC NH2 column with pentane and small additions of methanol as eluent. LC fractions were characterized by LC-GC-MS and quantitated by LC-GC-FID. The oil contained 23% aromatics and 1% “polars”; some 99.5% of the aromatics were alkylated.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 14 (1991), S. 558-559 
    ISSN: 0935-6304
    Schlagwort(e): Capillary GC ; Coupled LC-GC ; Contamination of solvent ; “Ghost” peaks ; “Fingerprints” ; 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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  • 7
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 15 (1992), S. 613-614 
    ISSN: 0935-6304
    Schlagwort(e): Press fit connections ; High temperature fused silica ; Polyimide ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Recently introduced fused silica, primarily of the high temperature type, no longer allows the formation of a reliable press-fit seal. Attempts to tighten the connection with various kinds of glue proved unsatisfactory. Manufacturers of fused silica tubing are urged to devote more attention to the problem.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 573-578 
    ISSN: 0935-6304
    Schlagwort(e): Large sample volumes ; Vaporizing chambers ; Evaporation rates ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The suitability of some chambers for sample evaporation at high input flow rates (〉100 μl/min) was studied by visual experiments. The chambers were at temperatures far above the solvent boiling point in order to achieve the heat transfer required. Shooting liquid owing to violent evaporation, flooding of the chamber as a result of cooling, and excessively high vapor pressure causing backflow into the gas supply system were found to be the limiting factors. Fused silica capillaries into which a piece of wire or polyimide-free fused silica capillary had been inserted were found to be suitable for the vaporization of “easy” solvents, such as alkanes (up to some 1.7 ml/min), but packed beds were required to achieve favorable evaporation of dichloromethane or methanol/water (up to some 800 and 300 μl/min, respectively).
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    ISSN: 1434-193X
    Schlagwort(e): Pyrido[3,2-f][1,4]thiazepine ; Carbon disulfide ; 1,4-Benzothiazepin-5(4H)-ones ; 2-Chloro-N-cyanomethyl-N-methylnicotinamide ; Aromatic nucleophilic substitution ; Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A new synthesis of pyrido[3,2-f][1,4]thiazepine derivatives 3 starting with 2-chloronicotinic acid (1), methylaminoacetonitrile hydrochloride and carbon disulfide is described. As proved by a crystal structure determination, a boat conformation with approximated mirror symmetry can be assigned to the 1,4-thiazepine ring in 3b. 2-Chloro-N-cyanomethyl-N-methyl-5-nitrobenzamide (5) reacts with carbon disulfide in presence of a strong base in DMF or DMSO depending on the temperature to either the benzothiopyran compound 6 or by intramolecular aromatic nucleophilic substitution to a seven-membered ring system as thiolate anion which can be alkylated to give the 1,4-benzothiazepine derivative 7, or to an open-chain amido ketene dithioacetal 8.
    Materialart: Digitale Medien
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  • 10
    ISSN: 0935-6304
    Schlagwort(e): Reversed phase LC-GC ; Vaporizer/percolumn solvent split/gas discharge system ; Phthalates in water ; Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Reversed phase liquid chromatography (RPLC) was coupled on-line to gas chromatography (GC) via the vaporizer chamber/preco-lumn solvent split/gas discharge interface outlined recently. Water-containing eluents were driven into a vaporizer chamber at 300°C by the LC pump. The Vapors were removed through an early vapor exist by the carrier gas. Solvent/solute separation occurred in hte retaining precolumn. Special attention was paid to the parame-ters determining the losses of the most volatile compounds. The oven temperature during transfer was lowered close to the dew point of the eluent (the temperature at which recondensation occurs) in order to maximise the retention power of the retaining precolumn. The dew point depends on the transfer rate, the gas flow rate, and the gas inlet pressure. Sometimes even better retention of the vola-tiles was observed at temperatures below the dew point, i.e. despite partial reconsideration. The method was applied to the analysis of phthalates in drinking and surface waters. The detection limits, using MS, were 5-10 ng/l.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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