• Proceedings of the Korean Journal of Food and Nutrition Conference
• /
• 2000.12a
• /
• pp.55-55
• /
• 2000

본 연구에서는 전통적으로 담석증, 신장치료 등의 한약제로 많이 사용하는 대왕을 여러 용매를 사용하여 얻은 대왕추출물 분액에 대한 세포독성을 여부를 MTT 정량법, NR 정량법, SRB 정량법을 이용하여 조사하였다. 1. 추출 용매 methylene chloride, ethyl acetate, butanol, water로부터 얻은 대왕추출물 모두 처리농도에 따라 세포에 미치는 영향이 증가하였다. 2. Butanol을 용매로 사용하여 얻은 대왕추출물 분액이 다른 3가지 용매로부터 얻은 대왕추출물보다 세포에 미치는 영향이 크게 나타났고 water를 용매로 사용하여 얻은 추출물이 A498 세포주에 미치는 영향이 가장 낮게 나타났다. 3. Butanol을 추출 용매로 하여 얻은 대왕추출물이 A498 세포주에 미치는 영향이 가장 컸는데 그 추출물에 대한 MTT50, NR50, SRB50값은 각각 0.63mg/m1, 0.65mg/ml, 0.68mg/ml이었고, 가장 영향이 적은 water의 경우 MTT50, NR50, SRB50값은 각각 0.84mg/m1, 0.82mg/m1, 0.80mg/ml이었다. 4. 정량방법 간의 대왕추출물에 대한 반응은 MTT 정량법이 가장 민감하게 나타났다.

• Journal of the Korean Chemical Society
• /
• v.39 no.8
• /
• pp.589-597
• /
• 1995

In water-ethanol systems, the limiting equivalent conductances of electrolytes were obtained using conductometric method. Using TATB method, the limiting equivalent ionic conductances of Li+, Na+, K+, Cl-, and Br- ions were also obtained. The effective radii of corresponding ions were determined using Nightingale method. From the volume of the solvation shell, the four solvation numbers were suggested. The reasonable solvation numbers (hH2O+hO) were estimated by comparing the values obtained by from the various suggested methods. The isosolvation point of ion in water-ethanol estimated was found to be larger than that of in water-methanol. This result agree with ET (solvent polarity) values of solvents. From the reasonable solvation numbers of ions in water-ethanol, the selective solvents of corresponding ions in water-ethanol were obtained.

• Proceedings of the Korea Association of Crystal Growth Conference
• /
• 1997.10a
• /
• pp.105-109
• /
• 1997

요소결정성장에 용매와 불순물이 주는 영향을 Monte Carlo법과 분자동역학법을 통해 분석하였으며 이를 통해 불순물인 Biuret이 결정의 Morphology에 대한 영향뿐만 아니라 내부격자에 용매인 물을 흡착시킨다는 것을 확인하였다. 또한 계면의 용매, 용질 그리고 격자층의 확산계수를 분석한 결과 용매인 물이 "Roughening Transition" 메커니즘으로 결정성장에 영향을 준다는 것을 밝혔다.다는 것을 밝혔다.

• Korean Journal of Food Science and Technology
• /
• v.47 no.2
• /
• pp.254-260
• /
• 2015

The effect of the extraction solvent on the physiological properties of the peel of the Korean pear (Pyrus pyrifolia cv. Niitaka) was evaluated. The total phenol content was highest in the 80%(wt) methanol extract, whereas flavonoid content was highest in the 80% ethanol extract. The antioxidant activities of the extracts were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging abilities, and their reducing power. The water and 80% methanol extracts of the pear peel had highest DPPH and ABTS radical scavenging activities, and reducing power, respectively. The inhibition of ${\alpha}$-glucosidase was highest in the 80% methanol extract, and alcohol dehydrogenase activity was highest in the water extract. All three extracts had similar antimicrobial activity. Because water, 80% ethanol, and 80% methanol extracts exhibited high activities in different assays of physiological properties, each solvent could be used for specific purposes.

• Korean Chemical Engineering Research
• /
• v.58 no.1
• /
• pp.92-97
• /
• 2020

In this study, the solubilities of a pharmaceutical compound, nifedipine, in three mixed solvents were determined. In addition, the nifedipine, that was dissolved in solvents (acetone, DMF, methylene chloride), was recrystallized using antisolvents (water, hexane, carbon dioxide) The external shape, size, and melting point of the crystallized nifedipine were measured. As the mixed solvents, acetone+water, DMF+water, and methylene chloride+hexane were used, and the solubility of nifedipine decreased with increasing antisolvent concentrations in the mixtures. In case of acetone+water, the solubility maximum was observed due to the density anomaly of the mixture, and this phenomenon was not observed in other systems. The crystallized nifedipine particles exhibited the bladed, equant, and prismatic habits, and the particles size was significantly reduced compared to the raw material. The average particle size of raw nifedipine was 337 ㎛, and the size of crystallized particles was in the range of 11.6~69.8 ㎛. All the crystallized nifedipine particles had the same thermal behavior and this result was not influenced by the change of solvent and antisolvent.

• Analytical Science and Technology
• /
• v.18 no.3
• /
• pp.194-200
• /
• 2005

The N hyperfine coupling constants ($a_N$) of di-t-butyl nitroxide (DTBN) radicals in water-solvent system were measured with EPR spectroscopy. Various kinds of the solvents with different polarity such as acetone, dimethylsulfoxide (DMSO), methanol, ethanol and 1-propanol were applied and studied. Equilibrium constants for the solvation equilibrium and the solvent parameters ($E_T$, molar transition energy) of various water-solvent system were obtained from the experimental results and are presented. The $a_N$ values were plotted as a function of mole fraction of the solvent. In case of water-DMSO, water-ethanol and water-1-propanol system, slight negative deviations from the straight line were observed. In water-acetone system, the absorption wavelength (${\lambda}$) due to ${\eta}{\rightarrow}{\pi}^{\ast}$ transition increased linearly with the increase of mole fraction of acetone. The relationship between $a_N$ of DTBN and ${\lambda}$ due to ${\eta}{\rightarrow}{\pi}^{\ast}$ transition in water-acetone and water-DMSO system was examined. It was found that the electronic structure of the nitroxide radicals is stablized from the fact that the N hyperfine coupling constants of DTBN radicals are greatly unaffected in the environment of water-solvent system.

• Journal of the Korean Chemical Society
• /
• v.35 no.5
• /
• pp.443-451
• /
• 1991

The solvation numbers of some ions in water and of KCl in mixed solvent systems were measured using the conductometric method. Stoke's radii of ions in solution were calibrated by the Nightingale method and the solvation numbers of ions in mixed solvents were deduced by simple assumptions. The deduced solvation numbers of each solvent reasonably go with its selective properties of solvation. From the isosolvation point of ions, the selective properties of ionic solvation were discussed.

• Journal of the Korean Chemical Society
• /
• v.27 no.3
• /
• pp.167-177
• /
• 1983

The kinetics of 2-anthracenesulfonyl chloride in methanol-water, ethanol-water, acetone-water and acetonitrile-water has been studied by electroconductometric method. For media in which water has the same mole fraction, the rate was greater in protic solvent than in dipolar aprotic solvent and it was greater consistently in methanol-water than in ethanol-water over the whole range of solvent composition investigated, while the two rates in acetone-water and acetonitrile-water inverted at about 0.9 of mole fraction of water. Both m value, susceptibility of rate to the ionizing power and n value, solvent participation number in the transition state were much smaller in protic solvent. These values and the activation parameters show that solvolysis of 2-anthracenesulfonyl chloride proceeds by $ S_N2$ mechanism.

• Journal of the Korean Chemical Society
• /
• v.37 no.8
• /
• pp.695-701
• /
• 1993

Rate constants of solvolysis of 2-thiophenesulfonyl chloride were determined in aqueous binary mixtures with methanol, ethanol, acetone in water and in methanol. These data are interpreted using the equation of Grunwald-Winstein and Kivinen relationship. Also, kinetic solvent isotope effects in water and in methanol and product selectivities in alcohol-water mixtures were determined. Kinetic solvent isotope effect for hydrolysis of 2-thiopenesulfonyl chloride was 2.24 and 1.47 for methanol and water, respectively. Selectivity values for formation of ester relative to acid in ethanol-water mixtures show maximum S value. From kinetic solvent isotope effect in methanol and water, selectivity data in aqueous alcoholic solvents and solvent effects, it is proposed that the reaction channel favoured in low polarity solvents is general-base catalysis and/or is possibly addition elimination (S$_A$N) reaction pathway and in high polarity solvents iS S$_N$2 reaction mechanism.

• Journal of the Korean Chemical Society
• /
• v.37 no.3
• /
• pp.309-316
• /
• 1993

The limiting equivalent ionic conductances of Li$^+$, Na$^+$, K$^+$, Cl$^-$, and Br$^-$ ions were obtained with TATB[Tetraphenyl Arsonium Tetraphenyl Borate] method from limiting equivalent conductances of LiCl, NaCl, KCl and KBr measured in water-methanol systems by conductometric method. With those values and viscosity of water-methanol systems, the Stokes radii of corresponding ions have been extracted. The latter values corrected by calibration method of Nightingale and supplemented by the crystallographic radii were utilized to calculate the volume of solvation-shell that surrounds ions. The reasonable solvation numbers (h$_{H_2O}$ ＋ h$_0$) were estimated by comparing the values obtained by the various suggested methods. The selective properties of ion solvation were also discussed.