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Adsorption Isotherms of Quercetin and Catechin Compounds on Quercetin-MIP

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Chemical Research in Chinese Universities 2007年第4期23卷 412-416页

作者： row kyung ho Center for Advanced Bioseparation Technology and Department of Chemical Engineering Inha University253 Yonghyun-DongNam-KuIncheon 402-751Korea

A molecular imprinted polymer（MIP） was prepared with quereetin as the template and methaerylie acid（MAA） as the functional monomer. Aeetonitrile and methanol were used as the porogen with ethylene glycol dimethaerylate （EGDMA） as the erosslinker and 2,2＇-azobis （ isobutyronitrile ）（ AIBN ） as the initiator. The experimental parameters of the equilibrium isotherms were estimated via linear and nonlinear regression analyses. The linear equadon as the functions of the adsorption concentration of the single compound in its solution and the competitive adsorption of the single compound in its mixed compounds solution was then expressed, and the adsorption equilibrium data were correlated to Langmuir and Freundlich isotherm models. The mixture compounds show competitive adsorption on the specific binding sites of quereetin-MIP. Furthermore, the competitive Langmnir isotherms were applied to the mixture compounds. The adsorption concentrations of quercetin, （＋）eatechin（＋C）, and （-）epieateehin（EC） on the quercetin molecular imprinted polymer were compared. The quercetin-imprinted polymer shows extraordinarily higher adsorption ability for quercetin than for the two eateehin compounds that were also assessed.

关键词： Adsorption isotherm Molecular imprinted polymer Quercetin (+) Catechin (-) Epicatechin

Evaluation of Retention Factors for Nine Solutes with Ionic Liquid Additives via Linear Solvation Energy Relationships

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Chemical Research in Chinese Universities 2010年第4期26卷 532-536页

作者： row kyung-ho Department of Chemical Engineering Inha University

A linear solvation energy relationships（LSERs） model was used to examine the fundamental chemical interactions governing the retention of 9 organic compounds on a C18 column by means of reversed-phase high performance liquid cbromatography（RP-HPLC）. Three ionic liquids, 1-hexyl-3-methylimidazolium tetrafluoroborate （[Hmin][BF4]）, 1-butyl-3-methylimidazolium tetrafluoroborate（[Bmin][BF4]） and 1-octyl-3-methylimidazolium tetrafluoroborate（[OMIm][BF4]） as additives, were added to a methanol-water mobile phase. The effects of these three ionic liquids additives on the retention of nine organic compounds were investigated, and a comparison between the predicted and experimental retention factors was made via the LSERs model, which indicated that the LSERs model could be used to reproduce the experimental retention factors of the solutes under different mobile phase conditions. It is also a useful tool for modeling the interactions of the solutes between the stationary and mobile phases and evaluating the retention characteristics of HPLC.

关键词： Retention factor Ionic liquid Additive Mobile phase Model

Optimization and Application of Liquid Chromatography Determination of Dispersive Liquid-liquid Microextraction Purified Astaxanthin in Shrimp Waste

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Chemical Research in Chinese Universities 2013年第3期29卷 429-433页

作者： ZHU Tao row kyung-ho School of Chemistry and Chemical Engineering Tianjin University of Technology Tianjin 300384 P. R. China Department of Chemical Engineering Inha University Incheon 402-751 Korea

A new molecularly imprinted solid-phase extraction（MISPE） monolithic cartridge was synthesized, and MISPE-DLLME（DLLME=dispersive liquid-liquid microextraction） was developed for purification of astaxanthin in shrimp waste. The eluent（methanol） from MISPE was used as the dispersive solvent in subsequent DLLME for further purifying and enriching the analyte prior to high-performance liquid chromatography（HPLC） analysis. The mobile phase was methanol-acetonitrile-water-dichloromethane（85：5：5：5, volume ratio）, flow rate was 0.7 mL/min and UV wavelength was 476 nm. Under optimal conditions, good linearity was obtained in a range of 0.2--200.0 lug/mL（r2=0.9998） with a limit of detection（LOD） of 0.08 Hg/mL, and the extraction recoveries at three spiked levels ranged from 88.3%--92.5% with a relative standard deviation（RSD） less than 4.3%. Moreover, the mean contents of astaxanthin in the three batches of shrimp waste were 95.9, 85.4 and 77.2 μg/g, respectively. This method combining the advantages of MISPE and DLLME results in high selectivity and low cost, which was applied to determining the astaxanthin level in shrimp waste samples.

关键词： Molecularly imprinted solid-phase extraction Dispersive liquid-liquid microextraction Astaxanthin Shrimp waste

Central Composite Design for Optimized Extraction of Polysaccharides from Undaria pinnatifida

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Chemical Research in Chinese Universities 2012年第4期28卷 620-623页

作者： HEO Hyo-jung row kyung-ho Department of Chemical Engineering Inha University253 Yonghyun-DongNam-KuIncheon 402-751Korea

Response surface methodology was used to optimize the extraction conditions of polysaccharides from Undaria *** effects of three independent variables,extraction time,extraction temperature and ratio of water to raw material were investigated by a central composite *** experimental data were fitted to a second-order polynomial equation via multiple regression analysis and also examined with the appropriate statistical *** adjusted coefficient of determination（R^2Adj） for the model was *** optimum extraction yield of 30.78% was obtained when the extraction temperature was 95 °C,extraction time was 4.5 h,and the ratio of water to raw material was 35（mL/g）.Under these conditions,validation experiments were done and the mean extraction yield of polysaccharides was 30.79%,which was in good agreement with the predicted model value.

关键词： Undaria pinnatifida Optimization Extraction Polysaccharide Response surface methodology

Purification of Astaxanthin from Laminaria japonica by Ionic Liquid-based Monolithic Cartridge

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Chemical Research in Chinese Universities 2012年第3期28卷 406-409页

作者： YOON Chang-hwan row kyung-ho Department of Chemical Engineering Inha UniversityIncheon 402-751Korea

An effective and accurate method was developed for the extraction of astaxanthin from Laminariajapo- nica with subsequent separation by ionic liquid-based monolithic cartridge. The optimized extraction conditions in- cluding extraction solvent（ethanol）, extraction time（90 min） and ultrasonic power（75 W） were obtained by systema- tical investigation. Chromatographic analysis was performed on a C18 column with ultraviolet（UV） detection at 476 nm, and a solution consisting of methanol/acetonitrile/H2O/dichloromethane（83：6：6：5, volume ratio） was used as the mobile phase at a flow rate of 0.7 mL/min. After ionic liquid-based monolithic solid phase extraction, 17.82 μg/g as- taxanthin was obtained from Laminaria japonica. This ionic liquid-based monolithic cartridge exhibits high affinity and selectivity for astaxanthin, and it can be potentially used as the stationary phase of high performance liquid chromatography（HPLC）.

关键词： Laminariajaponica Astaxanthin Extraction Ionic liquid Cartridge

Extraction and Purification of Depigmenting Agents from Chinese Plants

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Chemical Research in Chinese Universities 2006年第2期22卷 162-167页

作者： AHN So-young row kyung-ho KIM Eun-ki School of Chemical and Biological Engineering Center for Advanced Bioseparation Technology Inha University Nam-Ku Incheon 402-751 Korea

Depigmenting agents were solvent-extracted and purified by preparative and analytical HPLC from three Chinese plants; Chrysanthemum morifolium Ramat（ Xizang Caijuhua）, Rhodiola sachalinensis, and Terminalia chebula Retzius. Four fractions obtained from the ethyl ether layer of C. m. Rama and two fractions from the ethyl acetate layer of Rhodiola salientness show depigmenting effects. At 8 200, the ethyl acetate layers of Chrysanthemum morifolium Ramat, Rhodiola sachalinensis and the methanol extract of Terminalia chebula Retzius, can inhibit the melanin production of mouse B16 melanoma cells by 92%, 60% and 90%, respectively, whereas 46% inhibition was observed by commercially available depigmenting agents（arbutin）. These results show the potential of these three Chinese plants as a novel resource for depigmenting agents in the cosmetic industry.

关键词： Chrysanthemum Morifolium Ramat Rhodiola Sachalinensis Terminalia Chebula Retzius Melanin Inhibitory Effect HPLC

Comparison of Adsorption Isotherms of Methylxanthines on C_(18) Column

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Chemical Research in Chinese Universities 2010年第5期26卷 729-734页

作者： BI Wen-tao ChoI Dae Ki row kyung ho Department of Chemical Engineering Inha University lncheon 402-751 Korea Center for Fuel Cell Research Korea Institute of Science and Technology Seoul 136-791 Korea

A comparison of the adsorption isotherms of caffeine, theophylline and theobromine and the competitive adsorption of the three compounds on a C18 column were investigated. The experimental parameters of the equilibrium isotherms were estimated by linear and nonlinear regression analyses. The linear equation as a function of the adsorption concentration of the single compound in its solution and the competitive adsorption of a single compound in a mixed solution were then determined. The adsorption equilibrium data were then correlated to the linear, Langmuir, Freundlich, Langmuir-Freundlich and stoichiometric displacement theory for adsorption（SDT-A） isotherm models. The mixed compounds of the three compounds were competitively adsorbed on the C18 particles. The expression of stoichiometric displacement theory for adsorption was found to be more suitable for adsorption of methylxanthines on a C18 column.

关键词： Adsorption isotherm Methylxanthine High-performance liquid chromatography

Selective Solid-phase Extraction of Aloe Emodin from Aloe by Molecularly Imprinted Polymers

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Chemical Research in Chinese Universities 2013年第4期29卷 663-666页

作者： TIAN Ming-lei LEE Yu-ri PARK Dong-wha row kyung-ho College of Chemistry and Environmental Engineering Yangtze University Jingzhou 434023 P R. China Department of Chemical Engineering Regional Innovation Center for Environmental Technology of Thermal Plasma Inha University Ineheon 402-751 Korea

The extraction and separation of aloe emodin were optimized via selective molecularly imprinted solid-phase extraction. Molecularly imprinted polymer was prepared from the functional monomer, methacrylic acid and a mixture of ethanol/dodecanol（90/10, volume ratio） as porogen. It overcomes the common problems of imprin- ting biological polar compounds and shows high selectivity compared favorably with those of non-imprinted polymer and commercially available C18 and silica cartridges in similar aloe emodin tests. Good linearity was obtained be- tween 0.002 and 2.5 mg/mL（r2=0.998） with relative standard deviations below 3.3%.

关键词： Aloe emodin Molecularly imprinted polymer Solid-phase extraction High performance liquid chromato- graphy

利用HCI程序确定儿茶酚化合物的反相高效液相色谱最佳分离条件

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色谱 2006年第5期24卷 466-470页

作者：金银哲卢敬昊仁荷大学化工系及生物分离技术研究中心

有效地确定了反相高效液相色谱分离儿茶酚化合物的最佳条件。在水和甲醇的二元流动相里分别加入乙酸缓冲液,利用基于lnk=lnkw+SF,k=A+B/F,lnk=L+MF+NF2(F是流动相中有机物甲醇的体积分数)等保留因子的一次或二次方程式的塔板理论得到色... 详细信息

有效地确定了反相高效液相色谱分离儿茶酚化合物的最佳条件。在水和甲醇的二元流动相里分别加入乙酸缓冲液,利用基于lnk=lnkw+SF,k=A+B/F,lnk=L+MF+NF2(F是流动相中有机物甲醇的体积分数)等保留因子的一次或二次方程式的塔板理论得到色谱分离结果;利用保留原理得到等度和梯度洗脱的最佳条件。得出最佳初始流动相是含0.1%乙酸的水和含0.1%乙酸的甲醇(体积比为75∶25)的混合溶液;梯度洗脱条件:初始流动相保持15m in,然后用10m in的时间将上述二元流动相的体积比线性变换成50∶50,直到完成全部分离。通过实验证实该计算结果与实验值相近。

关键词：反相高效液相色谱儿茶酚化合物 HCI程序保留原理流动相组成