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  • Gas chromatography  (59)
  • Lunar and Planetary Science and Exploration
  • Mice
  • Springer  (60)
  • 1995-1999  (60)
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Keywords
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Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    CGC/AED and CGC/ECD/NPD comparison for the determination of acaricides in honey after hexane/acetone extraction (1996)
    Springer
    Chromatographia 42 (1996), S. 130-134 
    Details
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Atomic emission, electron capture ; and nitrogen phosphorus detection ; Honey ; Acaricides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The performance of a gas chromatographic system coupled to an atomic emission detector (GC/AED) is tested by comparison with a two-dimensional gas chromatographic system equipped with capillary columns of different polarity and simultaneous electron capture and nitrogen-phosphorus detection (ECD/NPD), for the determination of the acaricides chlordimeform, bromopropylate, amitraz and coumaphos on spiked honey samples. The acaricides were extracted with ann-hexane/acetone mixture (80∶20, v/v) with a further clean-up step on an octadecylsilane cartridge. The 193 nm carbon emission line is the best choice in terms of sensitivity whereas the ECD/NPD system gives better selectivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02269641
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  • 2
    Electronic Resource
    Electronic Resource
    Adrenal tissue in the male African catfish, Clarias gariepinus: localization and steroid hormone secretion (1995)
    Springer
    Cell & tissue research 280 (1995), S. 653-657 
    Details
    ISSN: 1432-0878
    Keywords: Adrenals ; Morphology ; Steroids ; Gas chromatography ; Mass spectrometry ; Clarias gariepinus (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Interrenal-like tissue in male African catfish is localized in paired organs, situated retroperitoneally anterior of the kidney. Histological and enzyme-histochemical (3β-hydroxysteroid dehydrogenase) reactions were carried out on sections of these organs in order to localize steroid-producing cells. In vitro incubations were carried out to determine the steroidogenic capacity of the interrenal-like tissue. Twenty-one steroids could be identified and quantified in the incubation medium, by means of gas chromatography followed by mass spectrometry. Cortisol, 5α-and 5β-androstanedione and androstenedione together comprised about 80% of the total steroid content. In a previous study, twenty testicular steroids were detected in plasma after castration. In the present investigation we have shown that most of these steroids can be produced by the interrenal-like tissue, which thus can be considered as an extra-testicular source of gonadal steroids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318367
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  • 3
    Electronic Resource
    Electronic Resource
    Adrenal tissue in the male African catfish, Clarias gariepinus: localization and steroid hormone secretion (1995)
    Springer
    Cell & tissue research 280 (1995), S. 653-657 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Adrenals ; Morphology ; Steroids ; Gas chromatography ; Mass spectrometry ; Clarias gariepinus (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Interrenal-like tissue in male African catfish is localized in paired organs, situated retroperitoneally anterior of the kidney. Histological and enzyme-histochemical (3β-hydroxysteroid dehydrogenase) reactions were carried out on sections of these organs in order to localize steroid-producing cells. In vitro incubations were carried out to determine the steroidogenic capacity of the interrenal-like tissue. Twenty-one steroids could be identified and quantified in the incubation medium, by means of gas chromatography followed by mass spectrometry. Cortisol, 5α- and 5β-androstanedione and androstenedione together comprised about 80% of the total steroid content. In a previous study, twenty testicular steroids were detected in plasma after castration. In the present investigation we have shown that most of these steroids can be produced by the interrenal-like tissue, which thus can be considered as an extra-testicular source of gonadal steroids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318367
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  • 4
    Electronic Resource
    Electronic Resource
    On-line solid-phase extraction-gas chromatography-ion trap tandem mass spectrometric detection for the nanogram per liter analysis of trace pollutants in aqueous samples (1997)
    Springer
    Chromatographia 44 (1997), S. 372-380 
    Details
    ISSN: 1612-1112
    Keywords: Solid-phase extraction ; Gas chromatography ; Ion trap tandem mass spectrometry ; Water samples ; Environmental analysis ; Pesticides ; Bromide ; Nitrite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary On-line solid-phase extraction-gas chromatographyion-trap tandem mass spectrometry (SPE-GC-MS/MS) has been used for the trace-level determination of polar and apolar pesticides. The SPE-GC interface, an Autoloop 2000, was operated at an injection temperature of 90°C which permitted the determination of thermolabile pesticides such as carbofuran and carbaryl. Rectilinear calibration curves were obtained for the analytes tested over a range of 0.1–500 ng L−1, using a sample volume of 10–100 mL for enrichment on an SPE cartridge packed with styrene-divinylbenzene copolymer. The detection limits for the pesticides were in the 0.01–4 ng L−1 range. For a number of pesticides acceptable tandem mass spectra were obtained at levels as low as 0.1 ng L−1 level in real-life water samples. As a demonstration of the applicability of this technique for inorganic anions, bromide and nitrite were converted into 4-bromoacetanilide and 2-phenylphenol, respectively. The reaction products were pooled and subjected to simultaneous analysis by the present method using full-scan mass spectrometric detection. The detection limits were 0.3 and 2 ng L−1, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02466313
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  • 5
    Electronic Resource
    Electronic Resource
    Data correlation in on-line solid-phase extraction-gas chromatography-atomic emission/mass spectrometric detection of unknown microcontaminants (1998)
    Springer
    Chromatographia 48 (1998), S. 273-283 
    Details
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Atomic emission and MS detection ; Solid-phase extraction ; Aqueous samples
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A procedure is described for the (non-target) screening of hetero-atom-containing compounds in tap and waste water by correlating data obtained by gas chromatography (GC) using atomic emission (AED) and mass selective (MS) detection. Solid-phase extraction (SPE) was coupled on-line to both GC systems to enable the determination of microcontaminants at the 0.02–1 μg L−1 level in 7–50 mL of aqueous sample. The screening was limited to compounds present in at least one heteroatom-selective GC-AED trace above a predetermined concentration level. These compounds were identified by their partial formulae (AED) and the corresponding mass spectra, which were obtained from the GC-MS chromatogram via the retention index concept. The potential of the approach was demonstrated by the identification of target compounds as well as all unknowns present in tap and waste water above the predetermined threshold of 0.05 μg L−1 (tap water) or 0.5 μg L−1 (waste water).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02467683
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  • 6
    Electronic Resource
    Electronic Resource
    Consequence of diluting modified β-cyclodextrins in a side-chain crown ether polysiloxane and in a side-chain liquid-crystalline polysiloxane-containing crown ether as stationary phases in capillary gas chromatography (1996)
    Springer
    Chromatographia 43 (1996), S. 546-550 
    Details
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Stationary phase ; Polysiloxane matrices ; β-Cyclodextrin ; Crown ether ; Liquid crystal ; Coordination effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary This paper investigates the possibility of using a sidechain crown ether polysiloxane (PDB-14-C4) and a side-chain liquid-crystalline polysiloxane-containing crown ether (PSC-3) as matrices for peralkylated β-CD employed as stationary phases. Three columns, coated with PSC-3 + permethylated β-CD, PDB-14-C4 + permethylated β-CD and PDB-14-C4 + perethylated β-CD were characterized by gas chromatography. The column efficiencies, phase transitions, and selectivities were measured and compared.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02293008
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  • 7
    Electronic Resource
    Electronic Resource
    Synthesis of chemically bonded squalene(ane) phases for microcolumn gas chromatographic separation of low-molecular-weight hydrocarbons in extraterrestrial atmospheres (1996)
    Springer
    Chromatographia 42 (1996), S. 141-146 
    Details
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Low-molecular-weight hydrocarbons ; Extraterrestrial atmospheres ; Chemically bonded squalene(ane) phase ; 13C and29Si CP-MAS NMR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Chemically bonded squalene(ene) phases have been synthesized via a hydride modified silanization process using dimethylchlorosilane, triethoxysilane and trichlorosilane. The surface structure of the bonded phases were characterized with DRIFT and solid state NMR studies. The results of the latter indicate successful bonding of a non-terminal olefin to the silica surface and that bonding of individual squalene molecules appeared not to occur at the same site(s) presumably due to steric hindrance. Among the phases examined, the trichlorosilane-based material exhibits better chromatographic properties probably due to greater surface coverage and hence effective non-polar interaction between the solutes and the bonded ligands. Under isothermal conditions, the present packings produced fast and efficient separation of C1–C4 saturated hydrocarbons on shorter columns than similar columns containing alkyl- or bidentate alkyl-modified silica packings at low column head pressure and are thermally stable at temperatures up to 250°C or higher.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02269643
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  • 8
    Electronic Resource
    Electronic Resource
    Autotrophic growth on carbon disulfide is a property of novel strains of Paracoccus denitrificans (1997)
    Springer
    Archives of microbiology 168 (1997), S. 225-236 
    Details
    ISSN: 1432-072X
    Keywords: Key words Paracoccus denitrificans ; Paracoccus ; versutus ; CS2 oxidation ; CS2 oxygenase ; Autotrophy ; 16S rRNA phylogeny ; Plasmids ; Megaplasmids ; Murein ; Gas chromatography ; SDS-PAGE profiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Three distinct strains (KL1, KS1, and KS2) of facultatively chemolitho-autotrophic bacteria able to use carbon disulfide or carbonyl sulfide as sole energy substrates were identified as novel strains of Paracoccus denitrificans. Evidence for their identity as biovars of P. denitrificans and as close relatives of Paracoccus versutus is based on their DNA composition, total sequencing of the genes for their 16S rRNA, muropeptide profiles, amino acid composition of peptidoglycan, kinetics of murein degradation by lysozyme, possession of large plasmids (91–98 kb) and megaplasmids (〉 450 kb), and plasmid transfer between the strains and with P. denitrificans and P. versutus. No functions have been identified for the 91- to 98-kb plasmids of strains KL1 and KS2, but curing strain KL1 of its plasmid did not affect growth on carbon disulfide, thiosulfate or succinate. Emendation of the formal description of Paracoccus denitrificans is presented. Autotrophic growth on carbon disulfide and thiosulfate was confirmed by 14CO2 fixation. Evidence is presented for initiation of carbon disulfide oxidation by an NADH-dependent oxygenase. Cell-free extracts catalyzed (1) NADH-stimulated uptake of oxygen in the presence of carbon disulfide, and (2) carbon-disulfide-stimulated oxidation of NADH. The activity was not sedimented at 50,000 ×g. Intermediates in aerobic carbon disulfide metabolism were shown by GC and GC/MS to include carbonyl sulfide and hydrogen sulfide, but anaerobic production of COS and H2S from carbon disulfide did not occur. SDS-PAGE of cell-free extracts showed polypeptides that were unique to growth on carbon disulfide, common to carbon disulfide and carbonyl sulfide, or found after growth on carbon disulfide, carbonyl sulfide or thiosulfate. The possible identity of these as proteins involved in sulfur compound metabolism is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002030050492
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  • 9
    Electronic Resource
    Electronic Resource
    Long-term restricted index selection in mice designed to change fat content without changing body size (1995)
    Springer
    Theoretical and applied genetics 91 (1995), S. 340-345 
    Details
    ISSN: 1432-2242
    Keywords: Selection index ; Restricted index ; Fat ; Mice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The objective of this study was to determine if low secondary selection differentials, caused by selecting within full-sib families, may have accounted for the failure of an intended restricted selection index to reduce epididymal fat pad weight (EF) without changing body weight (BW) in mice. Replicate lines that had been selected within full-sib families for high (HE) or low (LE) EF, while holding BW constant, were crossed. After two generations of random mating, two replicates were sampled and selection initiated for the same restricted index criteria except that mass selection was used to increase the selection differentials. In both phases of selection the HE restricted index selection, designed to increase EF without altering BW, was in agreement with expectation. In contrast, the LE index, designed to decrease EF without changing BW, did not agree with theory since BW increased while EF decreased only slightly. Therefore, reduced selection differentials could not explain the deviation from theory. A possible explanation may reside in the restricted selection index being more sensitive to changes in genetic parameters due to shifts in gene frequency as a consequence of the selection applied. However, linkage disequilibrium and genetic drift can not be ruled out as contributing factors to the asymmetry of response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220897
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  • 10
    Electronic Resource
    Electronic Resource
    Investigation of thermal and analytical properties of two nematic liquid crystals by gas chromatography (1995)
    Springer
    Chromatographia 40 (1995), S. 581-586 
    Details
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Liquid crystals ; Internal and external NO2 compounds ; Transition temperature ; Analytical properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Thermal and analytical properties of two liquid crystals containing internal [2-nitro, 3-methyl 4-(4-heptylbenzoyloxy) 4′-methylazobenzene] and external NO2 [2,3-dimethyl 4-(4-heptylbenzoyloxy) 4′-nitroazobenzene] have been investigated by gas chromatography. Transitions temperatures are determined by inverse gas chromatography using standard columns. Good agreement with values determined by differential scanning calorimetry are found. Analytical capabilities of the two liquid crystals are shown in glass capillary columns. Compared to examples in the literature, the crystals used separated different kinds of solutes. In addition, high molecular mass solutes were eluted at relatively low temperatures. Typical separations are observed for hydrocarbon positional isomers, aromatic hydrocarbons, geometric isomers, and volatile aroma compounds. Comparison between the performance of internal and external, NO2-liquid crystals is made.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02290272
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