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  • 1
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Size-exclusion chromatography ; Cellulose acetate packing ; Polymer separation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The elution characteristics of polymeric solutes or inorganic salts in high-performance liquid chromatography were examined with a cellulose acetate column using water as the mobile phase. Polymeric (PVP, PEG, etc.) and ionic solutes eluted in a shorter time than deuterium oxide. The retention times for polymers decreased continuously as the molecular weight increased. The elution characteristic, of polymers is assumed to be affected mainly by size exclusion effect. The retention times for ionic solutes increased with the concentration of the injected solutions and asymptotically approached some constant values. The retention times were also affected by the valence and/or hydration of the ion. It was suggested tha the exclusion of ionic solutes was caused by electric repulsion and/or hydration of ion. It was recognized that the salts which were excluded more strongly were rejected more effectively by cellulose acetate membrane in reverse osmosis. HgCl2 which is not dissociated in aquous solution was observed to be adsorbed strongly on cellulose acetate.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Cellulose acetate ; Acetyl content ; Temperature effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Cellulose and cellulose mono-, di-, and triacetate were used as stationary phases for liquid chromatography with water as a mobile phase, and the retention behavior of alcohols, ethers, ketones, and chlorides was examined. For cellulose acetate columns, the logarithm of the specific retention volume, (logV g * ), correlated linearly with the logarithm of partition coefficient between 1-octanol and water (log Ko/w), for each homologous group, but all solutes were unretained on cellulose columns. With the exception of chlorides, the intercept values of the log V g * –log Ko/w regression lines increased significantly with increase of acetyl content of cellulose acetates, but the slopes of the regression lines changed little. This suggests that hydrophobic interaction between the acetyl groups of cellulose acetates and the alkyl chains of the solutes is the dominant factor in the retention. The capacity factors for 1-alcohols with cellulos diacetate column indicated a maximum at a column temperature of about 40°C. This unique retention behavior was assumed to be caused by small structural change of the cellulose acetate polymer, because this temperature effect on the retention corresponded with effects observed by differential scanning calorimetry (DSC).
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  • 3
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; 1-Octanol/water partition coefficient ; Cellulose acetate ; Reverse osmosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The adsorption properties of esters, aldehydes, ethers and amides on cellulose acetate, which is commonly used as a reverse osmosis membrane material, in an aqueous solution system were measured by high-performance liquid chromatography. The adsorption property was characterized with the specific retention volume. For a noncyclic homologous series the logarithm of the specific retention volume was linearly correlated with the logarithm of the partition coefficient between 1-octanol and water. The fact that the slopes of these regression lines are almost identical confirms that the dominant effect on adsorption is the hydrophobic interaction between cellulose acetate and the solute molecule. The intercept represents the effect of the polar groups on adsorption. The effect of the polar group decreases as follows: ―C(O)O―, ―CO―, HCON〈 〉 CH3CON〈 〉 ―OH, ―O―.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Phytochemistry 22 (1983), S. 596-597 
    ISSN: 0031-9422
    Keywords: (6S)-2-methyl-6-[(1S)-4-methylene-2-cyclohexen-1-yl]-2-hepten-4-one. ; Curcuma longa ; Zingiberaceae ; bisabolane skeleton ; curlone ; sesquiterpenoid
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Phytochemistry 22 (1983), S. 596-597 
    ISSN: 0031-9422
    Keywords: (6S)-2-methyl-6-[(1S)-4-methylene-2-cyclohexen-1-yl]-2-hepten-4-one ; Curcuma longa ; Zingiberaceae ; bisabolane skeleton ; curlone ; sesquiterpenoid
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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