• Biotechnology and Bioprocess Engineering:BBE
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• 제9권1호
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• pp.47-51
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• 2004

Ceramide III was prepared by the cultivation of Saccharomyces cerevisiae. Ceramide III was partitioned from the cell extracts by solvent extraction and analyzed by Normal Phase High Performance Liquid Chromatography (NP-HPLC) using Evaporative Light Scattering Detector (ELSD). We experimentally determined the mobile phase composition to separate ceramide III with NP-HPLC. Three binary mobile phases of n-hexane/ethanol, n-hexane/lsoprophyl Alcohol(IPA) and n-hexane/n-butanol and one ternary mobile phase of n-hexane/IPA/methanol were demonstrated. For the binary mobile phase of n-hexane/ethanol, the first mobile phase composition, 95/5(v/v), was step-increased to 72/23(v/v) at 3 min. In the binary mobile phase, the retention time of ceramide III was 7.87min, while it was 4.11 min respectively in the ternary system, where the mobile phase composition of n-hexane/IPA/methanol, 85/7/8(v/v/v), was step-increased to 75/10/15(v/v/v) at 3 min. However, in the ternary mobile phase, the more peak area of ceramide III was observed.

• 공업화학
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• 제17권3호
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• pp.317-320
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• 2006

본 연구에서는 HCI프로그램을 이용하여 여섯 가지 퓨린 유도체(caffeine, guanine, hypoxanthine, purine, theobromine, and theophylline)의 최적 분석 조건을 결정하였다. 이동상으로 물과 메탄올을 사용하는 역상 HPLC를 사용하였다. 체류모델로는 Snyder, Langmuir, Binary polynomial 중에서 체류인자를 가장 잘 예측한 Binary polynomial을 사용하였고 용출곡선을 계산하기 위해서는 단 이론(plate theory)을 사용하였으며 모든 계산은 HCI 프로그램을 이용하여 계산하였다. 이동상의 조건은 일정용매조성법(isocratic mode)과 계단함수 구배용매조성법(step-gradient mode)을 이용하였다. 일정용매조성법에서 물과 메탄올의 조성비가 93/7 (v/v)일 때 최적 분석조건을 얻을 수 있었다. 분석시간의 단축을 위하여 계단함수 구배용매조성법을 사용하여 이동상의 조성을 물/메탄올 93/7 (v/v)에서 5 min 후에 75/25 (v/v)로 변경하는 최적조건을 계산했다. 위의 두 조건에서 실험을 수행하여 계산 용출 곡선과 실험값을 비교하였으며, 매우 잘 일치함을 보였다.

• Bulletin of the Korean Chemical Society
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• 제32권10호
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• pp.3597-3602
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• 2011

A simple and rapid analytical method was developed for the determination of eight isoquinoline alkaloids in Corydalis species. Eight isoquinoline alkaloids, including 2 aporphine alkaloids (isocorydine and glaucine) and 6 protoberberine alkaloids (coptisine, palmatine, berberine, canadine, corydaline, and tetrahydrocoptisine) were used as chemical markers which have a various biological activity and determined for quality control of Corydalis (C.) species (C. ternata, C. yanhusuo, and C. decumbens). To evaluate the quality of these herbal medicines, LC chromatographic separation of alkaloids were preferentially investigated on reversed-phase C18 column with pH variation and composition of mobile phase. In addition, the separation of these alkaloids in herbal extracts was found to be significantly affected on mobile phase composition using gradient elution. Especially for C. yanhusuo extract, berberine was seriously interfered with other alkaloid extracted from sample matrix when mobile phase composition was not optimized. As results, these compounds were successfully separated within 28 min using 10 mM ammonium acetate containing 0.2% triethylamine (adjusted at pH 5.0) as a mobile phase with gradient elution. On the basis of optimized HPLC conditions, 23 different Corydalis species samples were analyzed for the determination of alkaloid levels. In addition, principal component analysis (PCA) combined with the chromatographic data could be successfully classified the different geographic origin samples.

• KSBB Journal
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• 제18권5호
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• pp.408-411
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• 2003

피부미백효과 및 항산화물질로 알려진 glabridin은 감초뿌리 (Glycyrrhiza glabra)에 포함되어 있는 성분으로서 추출 및 HPLC에 의한 분리에 관한 연구 결과는 다음과 같다. 용매에 따른 추출정도를 알기위하여 메탄올, 에탄올, 에틸아세테이트 및 아세톤 등 4가지 용매로 1시간동안 초음파 추출하여 HPLC에서 비교 분석하였다. 그 결과 에틸아세테이트의 추출용매가 1260.0 mg/kg으로 가장 함량이 높았으며, 에탄올, 메탄올, 아세톤 순으로 나타났다. HPLC의 역상 컬럼에서 이동상의 조성을 아세토나이트릴/물 (50/50, vol. %)으로 사용했을 때 체류시간은 20.3분이였으며, 에틸아세테이트로 추출한 시험용액을 LC/MS로 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제15권1호
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• pp.15-20
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• 1994

The adsorption model in reversed phase liquid chromatography has been critically examined. It has been found that use of the Everett type surface activity coefficient for the solute in the stationary phase is not useful to study the retention characteristics of a nonpolar solute. We suggest a modified model. In this model it is assumed that the displaced modifier molecules from the surface monolayer do not transfer into the bulk mobile phase but stick to the nonpolar solute which has displaced them. In addition, we prefer to use an apparent stationary phase activity coefficient of the soluie instead of the Everett type activity coefficient. This modified adsorption model well explains the mobile and stationary phase effects on the solute retention upon variation of mobile phase composition.

• Bulletin of the Korean Chemical Society
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• 제30권9호
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• pp.2011-2016
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• 2009

To resolve the differentiation problem of acetone and acrolein in the analysis of carbonyls by high-performance liquid chromatography (HPLC), we investigated the optimum analytical conditions for their separation. Carbonyl compounds were collected by 2,4-dinitrophenylhydrazine (DNPH)-coated cartridges. We examined the influence of three experimental variables: temperature (25, 30, 40, 50 and 60 ${^{\circ}C}$), flow rate (1.0 and 1.2 mL/min), and relative mobile phase composition (among acetonitrile, water and tetrahydrofuran). The experimental results revealed the optimum analytical condition of a flow rate of 1.2 mL/min, temperature of 32 ${^{\circ}C}$ and mobile phase composition of acetonitrile: water: tetrahydrofuran = 34 : 52.8 : 13.2. The analysis of indoor air composition indicated that acrolein and acetone comprised 11% and 42% of all aldehydes, respectively.

• 분석과학
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• 제19권6호
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• pp.455-459
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• 2006

The extraction and separation of glabridin from licorice root by HPLC was performed in this work. First, by investigating the different extraction solvents, extraction methods and extraction times, a one-hour ultrasonic extraction procedure with ethyl acetate as the extraction solvent was optimized. Then the ethyl acetate extraction was applied to RP-HPLC for separation of glabridin. The column efficiencies and resolutions were experimentally investigated with different mobile phase compositions. Baseline separation of glabridin was obtained under the mobile phase composition of 50/50 vol.% (ACN/water). The retention time of glabridin was 20.3 min. The peak of glabridin was collected from the HPLC elution for several times and identified by LC/MS. Under the optimum extraction and HPLC separation methods, 1.26 g of glabridin per kg licorice root could be extracted.

• 한국대기환경학회지
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• 제34권4호
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• pp.616-624
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• 2018

In this study, a previous DNPH (2,4-dinitrophenylhydrazine) coupled with high performance liquid chromatography (HPLC) method to measure the concentration of formaldehyde in ambient and source environments has been improved. To improve the disadvantage of the previous HPLC method, an appropriate composition ratio of mobile phase (water: acetonitrile (ACN)) was determined and an isocratic analysis was conducted. Furthermore, limit of detection (LOD), limit of quantitation(LOQ), accuracy, and precision were investigated to verify the reliability of the analytical conditions determined. Finally, samples of exhaust gases from five different industrial facilities were applied to HPLC analytial method proposed to determine their formaldehyde concentrations. The appropriate composition ratio of the mobile phase under the isocratic condition was a mixture of water(40%) and ACN(60%). As the volume fraction of the organic solvent ACN increases, retention time of the formaldehyde peak was reduced. Detection time of formaldehyde peak determined using the proposed isocratic method was reduced from 7 minutes(previous HPLC method) to approximately 3 minutes. LOD, LOQ, accuracy, and precision of the formaldehyde determined using standard solutions were 0.787 ppm, 2.507 ppm, 93.1%, and 0.33%, respectively, all of which are within their recommended ranges. Average concentrations of the formaldehyde in five exhaust gases ranged from 0.054 ppm to 1.159 ppm. The lowest concentration (0.054 ppm) was found at samples from waste gas incinerator in a bisphenol-A manufacturing plant. The highest was observed at samples from the absorption process in manufacturing facilities of chemicals including formaldehyde and hexamine. The analytical time of the formaldehyde in ambient air can be shortened by using the isocratic analytical method under appropriate mobile phase conditions.

• Bulletin of the Korean Chemical Society
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• 제26권2호
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• pp.297-302
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• 2005

The determination of total phenols was accomplished by capillary-high performance liquid chromatography (capillary-HPLC) after nitrosation of the U.S.E.P.A. classified 11 priority pollutant phenols, using the nitrosated parent phenol (POHNO) as a reference for calibration. The optimum mobile phase composition for this analysis was found by examining the effect of changing the percentage of acetonitrile (MeCN) in the mobile phase on retention factors (k values) and peak intensities. As MeCN percentage was increased, k values were reduced and peak intensities were generally increased. From the results obtained, it was found that the optimum mobile phase was 90%(v/v) MeCN solution at pH 8.0, the detection wavelength of 400 nm, and a detection limit (D.L., concentration at signal to noise ratio (S/N) of 3.0) of 4.5 ${\times}$ $10^{-7}$ M. In addition, 10 of the 11 phenols present in mineral or waste water were separated after the nitrosation by capillary-HPLC. The optimum mobile phase for separation was a 40%(v/v) MeCN solution at pH 5.0.

• KSBB Journal
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• 제14권1호
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• pp.17-23
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• 1999

초임계 이산화탄소 크로마토그래피 방법에 의한 paclutaxel baccatm III, 7-epn-10-deacetyltaxol.cephalomanme, 10-deacetyltaxol의 분리에서 초임계 유체의 압력, 온도 및 이동상의 조성이 미치는 영향을 연구하였다. Pachaxel, 10-deacetylbaccatin III, 10-deacetyltaxol은 압력, 온도, 이동상의 조성 변화에 의하여 우수한 분리 결과를 얻을 수 있었다. Pacltaxel 의 경우 압력 275kg/$\textrm{cm}^2$,온도 $40^{\circ}C$, 이동상 조성을 초기 20분간 초임계 이산화탄소와 보조용매인 메탄올을 각각 3.9~3.6mL/min, 0.1~0.4mL/min의 gradienl조건으로 하였을 때 가장 우수한 분리능을 보였다. Baccatin III, caphalomamine, 7-epn-10-deacetyltaxol의 경우에는 낮은 분리능을 보였다. 주목 분말 시료로부터 paclitaxel 을 정제할 때 on-linc coupled SFE/SFC장치를 이용하여 추출 정제 공정을 단순화하였다. 초임계이산화탄소를 용매로하여 추출, 1차 정제 및 크로마토그래픽 정제 단계를 연속적으로 거쳐 38%수율로 95%paclitazel을 얻을 수 있었다.