• Journal of the Korean Chemical Society
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• v.38 no.8
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• pp.562-569
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• 1994

The retention data of twenty one monosubstituted phenols in the eluent systems containing 30∼70% of methanol or acetonitrile as organic modifiers, on $ C_{18}$ and Phenyl columns were collected to investigate the effect of the substituted groups on the retention of phenols. The capacity factors of the solutes except amino phenols are greater on $ C_{18}$ than on Phenyl column. And all the solutes have shown greater capacity factors in methanol-water than that in acetonitrile-water as a mobile phase. Generally the elution order between meta and para isomers of monosubstituted phenols in consistent (p < m) regardless of the polarity of the substituted group. But the elution order between ortho and meta isomers of phenol varies with regard to the polarity of the substituted group. The retention of the monosubstituted phenols has been influenced by the interaction between the solute and unreacted silanol of columns as well as the interaction between the solute and $ C_{18}$ or phenyl group of columns. And then, the effect of unreacted silanol on the retention of the monosubstituted phenols is greater on $ C_{18}$ than on Phenyl column. And the greater hydrogen bonding acceptor basicity(${\beta}$) of the substituted group is, the greater this effect is. The relationship between the retention of the monosubstituted phenols and their parameters such as van der Waals volume(VWV) and hydrogen bonding acceptor basicity(${\beta}$) has been investigated. The good linearity has been observed in the plot log k' vs. (1.01VWV/100-1.84${\beta}$). In consequence, the retention of the monosubstituted phenols on $ C_{18}$ and Phenyl columns can be easily predicted by the parameter (1.01VWV/100-1.84${\beta}$).

• Proceedings of the EASDL Conference
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• 2004.10a
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• pp.107-129
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• 2004

Sesame oil has been popular for hundreds of years in Korea because of its pleasant flavor and health benefits and has been studied for its antioxidant properties and flavor preferences attributed to its manufacturing methods. The objective of this study was to investigate the qualitative properties of six commercial sesame oils (3 Korean, 2 Japanese, 1 Chinese), The fatty acids in the oil are composed of two main acids oleic acid and linoleic acid with a P/S ratio of 4.99${\sim}$5.73. Of the tocopherol isomers, ${\gamma}$-toc ranged from 23.14 to 34.85mg/100g. Lignan such as sesamin(322.91${\sim}$689.39ppm) and sesamolin (62.19${\sim}$289.82 ppm) is found predominantly in sesame oil. Sesamol (8.52${\sim}$51.21 ppm) was significantly different depending on manufacturer, observed as greatest in the Korean and least in the Japanese products. The induction period was longest in order of the Korean, Chinese, and then Japanese product. The red and yellow values in Lovibond color were highest in the Korean and lowest in the Japanese product. The major volatile compounds (in order of content) were pyrazines, phenols, aldehydes, and then furans and contained a small amount of pyrroles, thiazoles and indoles. The levels of total volatiles were greatest in the Korean and least in the Japanese product. The most abundant volatiles in the Korean product were pyrazines, whereas phenols were higher in the Chinese product compared to the others. From these results, the relationships among pyrazines, sesamol, yellowness and induction period showed positive, respectively. In sensory evaluation, Korean panelists preferred, in order, the Korean, Japanese, and then the Chinese product in strength of and preference for the sesame flavor, also ranking it best in overall acceptance. Japanese panelists found similarities in the Korean and Japanese products and gave an equal level of preference for the sesame flavor and overall acceptance. On the other hand, Chinese panelists preferred the Japanese product in strength and sesame flavor rating it best on overall acceptance.