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  • 1
    ISSN: 1520-5851
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Industrial & engineering chemistry research 30 (1991), S. 2133-2137 
    ISSN: 1520-5045
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Industrial & engineering chemistry research 31 (1992), S. 2127-2133 
    ISSN: 1520-5045
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Industrial & engineering chemistry research 31 (1992), S. 1045-1050 
    ISSN: 1520-5045
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Geo-marine letters 16 (1996), S. 11-16 
    ISSN: 1432-1157
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Dissolved material and recent sediment from the Amazon continental shelf have been analyzed for hydrocarbons to study the sources and potential fate of the transported organic matter. Dissolvedn-alkanes are present at low concentrations (ppb level) and are dominated by lipids from marine phytoplankton with carbon number maxima (Cmax) at C18/C22 and an even-to-odd carbon predominance 〈 C30 (CPI17–27 from 0.18 to 0.54). In the sediments, bimodal distributions ofn-alkane chain length suggest a mixed input of terrestrial (Cmax at C27/C29/C31 and CPI25–33 from 0.75 to 1.82) and phytoplanktonic/microbial (Cmax at C20 and CPI15–25 from 0.38 to 0.62) organic matter. Sesquiterpenes were the most significant cyclic compounds in all the dissolved samples analyzed reflecting a contribution from resinous trees to the terrestrial organic pool. On the other hand, enhanced concentrations of these compounds in the dissolved phase on the northwest portion of the Amazon shelf, contrasting with decreased concentrations in the sediment samples, suggest that dissolved lipids are released from solid phase in the intensely stirred seabed. Structured organic matter in the sediment has been characterized as being composed of, on average: 19% plant cuticles, 25% woody tissue, 13% pollens and spores, 24% amorphous material, 7% bituminite and 12% altered organic material.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 20 (1997), S. 305-309 
    ISSN: 0935-6304
    Keywords: HRGC ; GCMS ; XAD-2 ; Sesquiterpenes ; Sesquiterpenoids ; Volatile lipids ; Biomarkers ; Amazon ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In order to evaluate vloatile compounds, especiallly sesquiter-penoids, in environmental and geological samples a method was penoids, in environmental and geological samples a method was required to characterize these components when they occur at low concentrations. After fractionation of the total sample extracts by TLC the aliphatic fractions were analyzed by HRGC AND THE kovats indices of all resolved peaks were calculated and comkpared with indices of all resolved peaks were calculated and compared with those obtained for commercial standards. As final step, the fractions were analyzed by HRGC-MS and structures confirmed by comparison of their mass spectra with those of certified sesuiterpene standards. Additionally sesquiterpenoids present in the dissolved phase in water samples were concentrated by solid phase extraction using XAD-2 resin. In this initial study, recovery tests with the resin were carried out in order to evaluate its performance rather than validating the methodology.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 15 (1992), S. 256-259 
    ISSN: 0935-6304
    Keywords: Gas chromatography ; High temperature ; Narrow bore glass columns ; CH3O-terminated polysiloxane, PS-090 ; Triglycerides ; Free base porphyrins ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The use of high-temperature-stable, medium polarity glass capillary columns coated with immobilized PS-090 (a 20 % diphenyl-substituted, CH3O-terminated polydimethylsiloxane) has made it possible to analyze routinely, and with good separation efficiency, high molecular weight compounds such as triglycerides and free base porphyrins. Cold on-column injection was used throughout this work to avoid discrimination against involatile compounds, and disposable (fused silica) retention gaps were used to protect the column against contamination with involatile material. On-column injection into narrow bore glass columns was achieved by using glass-to-silica connections to attach wider bore (0.2 mm i.d.) deactivated fused silica tubing to the columns.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0935-6304
    Keywords: high temperature capillary GC ; high temperature capillary GC-MS ; organic tracers ; OV-1701-OH ; smoke aerosols ; triglycerides ; wax esters ; triterpenyl esters ; Amazon ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A custom-made glass capillary column coated with OV-1701-OH (88% methyl, 7% cyanopropyl, 5% phenylpolysiloxane) was used to analyze smoke samples from biomass combustion of different species of plants collected in the Amazon forest. CS2 was used as solvent in order to enhance the dissolution and analysis of the heavier molecular weight components. The performance of the column was monitored during the experiments and a moderate increase in activity was observed after taking the column to high analytical temperatures (390°C). Trennzahl values typically dropped 20-30% from 1.7/m to the average of 1.35/m. In general, the performance of the custom-made column was satisfactory and comparable to the commercial high temperature columns. The high temperature high resolution GC and GC-MS analyses revealed the presence of a number of high molecular weight components reported to occur in smoke aerosols for the first time. These components consisted of series of wax esters (long chain alcohols esterified with long chain fatty acids) with up to 58 carbon numbers, aliphatic hydrocarbons, triglycerides, triterpenyl esters (e.g. α- and β-amyryl stearate). Although other types of compounds were also detected, their complete structure elucidation solely by electron impact MS was not adequate and other techniques will be required.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0935-6304
    Keywords: Cold on-column injector ; high temperature high resolution gas chromatography ; rotenoids ; PS-090 ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---A short glass capillary column coated with PS-090 (20% phenyl-80% methylpolysiloxane, of 10 m × 0.30 mm i.d.; with 0.1 μm film thickness) was used to analyze samples from Tephrosia candida; eighteen rotenoids were separated and identified without derivatization by HT-HRGC and HT-HRGC-MS. The mass spectra show the typical fragmentation pattern for rotenoids, with the base peaks either at M+, or originating from RDA (Retro Diels-Alder) rearrangements. HT-HRGC and HT-HRGC-MS were shown to be extremely valuable and neglected techniques for structural studies as well as the routine analysis of rotenoids in crude extracts. Possible applications to other classes of aromatic natural products, e.g. flavonoids, are envisaged.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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