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  • Analytical Chemistry and Spectroscopy  (11)
  • bic Book Industry Communication::J Society & social sciences::JN Education  (6)
  • 2020-2024  (6)
  • 1995-1999  (10)
  • 1975-1979  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 501-503 
    ISSN: 0935-6304
    Keywords: High resolution GC-MS ; Mass spectrometry ; Anise oil ; Catalytic transformation ; Zeolite Y ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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  • 2
    Publication Date: 2024-03-29
    Description: Based on the roots and convictions of the researchers - the rhizomatic study ventured into the identification and recovery of Afro-Colombian ancestral values in the Pacific Region (Colombia), generating two sequential and complementary stages for this purpose: language contact with elders and older adults from two Ancestral Black Communities Councils in Buenaventura and in La Playa respectively (Valle-Colombia), and the subsequent pedagogical mediation with young people from the Ancestral Black Communities Council of La Bocana (Valle-Colombia). From a rhizomatic methodological structure based on the positions of Deleuze andGuattari (2005), the respective interactions were conducted in a holistically way, under the recovery of human networks and language, in addition to dynamics such as the cane handover, all of the former with strong roots in the praxis of Afro-Colombian communities in general. The obtained results led to significant findings both at the axiological level, and in the terms of emerging cultural elements, in its final phase the research allowed to assertively show the realization of padagogical mediations achieving to reaffirm and recover the Afro-Colombian ancestral values in the context of their new generations.
    Description: Published
    Description: Dadas las raíces y convicciones de los investigadores, el estudio rizomático incursionó en la identificación y recuperación de los valores ancestrales afrocolombianos en la Región Pacifico (Colombia), generándose para el efecto dos etapas secuenciales y complementarias: el contacto de lenguajeo con ancianos y adul-tos mayores de dos Consejos Comunitarios Ancestrales de Comunidades Negras, respectivamente de Buenaventura y de La Playa (Valle–Colombia), y la posterior mediación pedagógica con jóvenes del Consejo Comunitario Ancestral de Comunidades Negras de La Bocana (Valle–Colombia). Desde una estructura metodológica rizomática asentada en las posturas de Deleuze y Guattari (2005), las respectivas interactuaciones de adelantaron de manera holística, bajo la recuperación de tejidos humanos y lenguajeos, además de dinámicas como el paso del bastón, todas con fuerte arraigo en las praxis de las comunidades afrocolombianas en general. Los resultados obtenidos conllevaron a significativos hallazgos tanto a nivel axiológico, como en cuanto a elementos culturales emergentes, y siendo que en su fase final la investigación permitió mostrar de manera asertiva la realización de mediaciones pedagógicas que logran reafirmar y recuperar los valores ancestrales afrocolombianos en el contexto de sus nuevas generaciones.
    Keywords: Afrocolombianos ; Identificación ; Recuperación ; Región Pacífico ; Valores Ancestrales ; bic Book Industry Communication::J Society & social sciences::JN Education ; thema EDItEUR::J Society and Social Sciences::JN Education
    Language: Spanish
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 19 (1996), S. 353-358 
    ISSN: 0935-6304
    Keywords: Capillary gas chromatography ; Gas chromatography-mass spectrometry ; Essential oil analysis ; Ylang-ylang oil ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Steam distillation (SD), simultaneous distillation-solvent extraction (SDE), and supercritical (CO2) extraction (SFE) were used to isolate volatile secondary metabolites from fresh, totally mature flowers of Colombian ylang-ylang (Cananga odorata). The various extracts were analyzed by capillary chromatography (DB-1, DBWAX, 60 m columns) using FID, NPD or MSD (EI, 70 eV). Kováts indexes, mass spectra, or standard substances were employed for compound identification. 51, 70, and 73 compounds at concentrations above 100 ppb were detected in the SD, SDE, and SFE extracts, respectively. The main constituents of these extracts were linalool (20.7, 28.0, and 16.5%), germacrene-D (10.1, 3.1, and 20.3%) benzyl benzoate (14.1, 2.9, and 3.9%), benzyl acetate (9.6, 17.0, and 6.2%), caryophyllene (3.1, 2.9, and 3.9%), and p-methylanisole (6.8, 6.1, and 2.7%). 85% of the composition of SDE extracts was represented by oxygenated compounds. Heavy hydrocarbons (Cn 〉20) and fatty acids were found only in the SFE extracts, which also had a higher content of nitrogenated compounds (phenylacetonitrile, 4-methylbenzaldoxime, indole, 2-phenyl-nitroethane, and methyl anthranilate) and sesquiterpenes (43% vs 19.5% in SD and 8.1% in SDE) and 1.5 - 2 times lower concentration of monoterpenes and light oxygenated compounds than the SD (49.7%) and SDE (64.5%) extracts.
    Additional Material: 4 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 675-678 
    ISSN: 0935-6304
    Keywords: Capillary zone electrophoresis (CZE) ; Stacking effect ; Cationic surfactant ; Cr(VI) ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
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  • 5
    ISSN: 0935-6304
    Keywords: Capillary gas chromatography ; gas chromatography-mass spectrometry ; essential oil analysis ; Lepechinia schiedeana ; antioxidant activity ; lipid peroxidation ; Ledol; Ledol HMQC ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---Steam distillation (SD), simultaneous distillation-solvent extraction (SDE), microwave-assisted solvent extraction (MWE), and supercritical (CO2) extraction (SFE) were used to isolate secondary metabolites from Lepechinia schiedeana. The various extracts were analyzed by capillary gas-chromatography, on poly (dimethylsiloxane) (DB-1) and poly(ethyleneglycol) (INNOWAX), 60 m columns, using FID or MSD (EI, 70 eV). Kováts indexes, mass spectra, or standard compounds were employed for compound identification. 43, 61, 67, and 79 compounds at concentrations above 0.01% were detected in the SD, SDE, MWE, and SFE extracts, respectively. Ledol, C15H26O, was the major constituent (20.04-36.87%) in all extracts. Oxygenated sesquiterpenes (24.36-43.14%), C10H16, monoterpenes (27.70-39.87%), and C15H24, sesquiterpenes (10.04-22.22%) were the main groups of compounds present in SD, SDE, MWE, and SFE extracts. Heavy hydrocarbons (Cn 〉 15), diterpenoids, and phytosterols were found only in MWE and SFE extracts. The antioxidant activity of Lepechinia schiedeana was measured by the HRGC quantification of the volatile carbonyl compounds, final products of lipoxidation, released in a model lipid system (sunflower oil) by the effect of the Fenton reagent. The concentration of volatile carbonyl compounds decreased by 65% when lipid oxidation was induced in the presence of macerated Lepechinia plant. The protection of polyunsaturated acids in sunflower oil was also studied by measuring their concentrations after heating of the oil (180°C, 2 h) with and without macerated Lepechinia plant.
    Additional Material: 4 Ill.
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  • 6
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Endogenous tryptamine, 5-hydroxytryptamine, indoleacetic acid, 5-hydroxyindoleacetic and tryptophan have been recovered from urine and cerebro-spinal fluid by adsorption on XAD-2 resin (0.3 g). After adsorption of the sample on the resin, desorption with methanol provides a single fraction that contains all of these metabolites. The mass spectra of their pentafluoropropionyl derivatives show prominent ions at m/e 276 and 438 which are characteristic of indoles and 5-hydroxyindoles, respectively, a feature that allows the concurrent determination of all the components of each group by functional group analysis. A method has been developed to carry out single ion monitoring with the peak matching system of an Hitachi RMU-6H mass spectrometer. Identifications are based on the respective Kovats Indices and single ion monitoring of two characteristic ions per compound: tryptophan (m/e 276 and 347); tryptamine (m/e 276 and 289); indoleacetic acid (m/e 276 and 335); 5-hydroxytryptamine (m/e 438 and 451); 5-hydroxyindoleacetic acid (m/e 438 and 497). The method described illustrates the feasibility of assaying biogenic indoleamines and acidic metabolites, as well as their precursor amino acid on a single fraction in contrast to other standard fractionation methods. This is possible even if the mass spectrometer is not equipped with an alternating voltage accelerator provided that it has a peak matcher, although the lack of an alternating voltage accelerator requires two separate injections of the same sample, for quantification and identification; one for the indole profile and another for the 5-hydroxyindole profile. Both profiles can be verified by individual monitoring of the other confirmatory ions. With this method the use of a multiple ion detector would allow a simultaneous determination of all of these metabolites in one gas chromatograph mass spectrometer run.
    Additional Material: 3 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 9 (1995), S. 509-511 
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The reduction phenomenon of polar compounds that has already been described in fast-atom bombardment (FAB) mass spectrometry also occurs in frit-FAB mass spectrometry.
    Additional Material: 2 Ill.
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  • 8
    ISSN: 0935-6304
    Keywords: Chiral GC ; chiral stationary phase ; cyclodextrin ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: ---2,3-Di-O-pentyl-6-O-tert-butyldimethylsilyl-β-cyclodextrin has been evaluated as an enantioselective stationary phase for capillary gas chromatography. Experimental results show a good enantioselectivity towards compounds with different functional groups (haloalkanes, alcohols, esters, terpenoids, amino acid derivatives, and heterocycles). Column stability improves mixing the chiral phase with polysiloxane SE-54 (1 : 1).
    Additional Material: 2 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 18 (1995), S. 54-58 
    ISSN: 0935-6304
    Keywords: High resolution capillary GC ; High resolution GC-MS ; Zeolite ZSM-5 ; Copaiba tree (Copaifera officinalis) ; Copaiba oil ; Fuel oil ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The oil extracted from the trunk of the copaiba tree (Copaifera officinalis) is composed of sesquiterpenes, C15H24, and a small amount (〉7 %) of sesquiterpenols, C15H26O; these were identified from their Kováts indices and mass spectra. The use of zeolites in the catalytic transformation of this renewable source of hydrocarbons is of interest in the search for new chemicals and ecologically clean fuels. Oil samples from copaiba trees growing in Colombia's Oriental Plains were circulated over zeolite ZSM-5 in a continuous flow fixed-bed micro reactor at 225, 265, and 325°C, for 1 h and subsequently analyzed by HRGC and GC-MS. Whereas only thirty four sesquiterpenes were identified in the original oil, over two hundred compounds were found in the product of the treatment of copaiba oil with zeolite ZSM-5. This complex mixture of sesquiterpenes, light aromatic compounds, and indene and naphthalene derivatives resulted from reactions such as isomerization, hydrogenation, cracking, and dehydrogenation with and without cracking. The amount of cracking products and aromatic compounds increased with reactor temperature but decreased with catalyst aging.
    Additional Material: 4 Ill.
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  • 10
    ISSN: 0935-6304
    Keywords: High resolution capillary GC ; High resolution GC-MS ; Essential oil analysis ; Ylang-ylang oil composition ; Cananga odorata ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Volatile secondary metabolites from Colombian ylang-ylang flowers were obtained by combined steam distillation - solvent extraction. The samples were analyzed by high resolution gas chromatography with flame ionization, nitrogen/phosphorus, or mass spectrometric detection. The chemical composition of the oils extracted from flowers at different stages of development differed both qualitatively and quantitatively. The generation of total volatile metabolites, light oxygenated compounds in particular, increased markedly during flower maturation. In this work the quality of the ylang-ylang essential oils was studied as a function of flower maturity.
    Additional Material: 3 Ill.
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