• Bulletin of the Korean Chemical Society
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• 제29권5호
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• pp.979-984
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• 2008

In this study, 8 solutes (aniline, caffeine, p-cresol, ethyl benzene, methylparaben, phenol, pyridine, and toluene) have been tested in terms of linear solvation energy relationships (LSER). Several micellar liquid chromatography (MLC) systems using cationic surfactant cetyltrimethylammonium bromide (CTAB) and a mixture of water with (methanol, n-propanol, and n-butanol) modifiers were characterized using the LSER solvation parameter model. The effects of the surfactant and modifier concentration on the retention in MLC were discussed. LSER model had demonstrated high potential to predict retention factors with high squared correlation coefficients ($r^2$ > 0.99). A comparison of predicted and experimental retention factors suggests that LSER formalism is able to reproduce adequately the experimental retention factors of the solutes studied in the different experimental conditions investigated. This model is a helpful tool to understand the solute-surfactant interactions and evaluate the retention characteristic of micellar liquid chromatography.

• 분석과학
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• 제6권3호
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• pp.267-274
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• 1993

두 가지 파라미터를 이용한 반복 회귀 최적화법을 미셀 액체 크로마토그래피에서 아미노산과 팹티드류의 분리에 적용하였다. 실험에 사용한 파라미터들은 계면활성제(surfactant)인 SDS와 2-propanol의 농도이다. 이 최적화 방법은 작은 횟수의 초기 실험 수행으로 효과적인 최적화점을 얻을 수 있었다.

• 분석과학
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• 제6권1호
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• pp.1-8
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• 1993

음이온 계면활성제인 sodium dodecyl sulfate(SDS)를 이동상으로 한 미셀 액체 크로마토그래피(micellar liquid chromatography : MLC)에서, 시료로 22종의 페놀과 벤젠 일치환체들을 선택하여 이 시료들의 용리거동을 조사하여 MLC계에서의 소수성 효과를 알아 보았다. MLC에서의 머무름과 미셀 농도간의 상관관계를 통해 시료들이 미셀-물간, 변형된 정지상-물 사이에서 분배될 때의 분배계수를 구하였고, 또 이를 이용하여 물-미셀간의 전이 자유 에너지를 구하였다. 이러한 MLC에서 얻은 소수성 파라미터들은 옥탄올-물계와 연관시켜 본 결과 좋은 상관관계를 보였다. 따라서 이 두 계에서 시료의 소수성이 머무름에 중요한 영향을 미침을 알 수 있었다. 한편, MLC를 이용하면 quantitative structure activity relationships(QSAR)에서의 소수성 정량 연구에 적용이 가능하다. 또한 알킬 치환체들에서 탄소 수의 증가에 따른 머무름 관계를 통하여 소수성의 선택성을 알아 보았고, 유기 변형제로 n-프로판올을 첨가하였을 때에도 마찬가지로 MLC계에서의 소수성 파라미터와 옥탄올-물계 사이에 상관관계가 있음을 알았다.

• 대한화장품학회지
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• 제12권1호
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• pp.34-61
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• 1986

The microstructural transitions of aqueous micellar solutions of cetyltrime-thylammonium bromide and sodiumdodecyl sulfate by adding 1-hexanol were investigated, measuring the concentrations of equilibrated phases and the electrical conductivities at the low concentrations of surfactants, where the solobilities of 1-hexanol varied significantly, at 3$0^{\circ}C$ and 45$^{\circ}C$. Ternary phase diagrams of multiphase regions, constructed by liquid chromatography analysis and by counting the number of phase of samples, consisted of one three-phase region and three two-phase regions. One of the two-phase regions was found to equilibrate an aqueous micellar solution and a liquid crystal, and had a critical point between them. Near this region, the solubility curve varied abruptly, and the isotropic solution turned birefrigent. The conductivities of the single phase regions above the critical point increased up to a certain point as 1-hexanol added, and then decreased, representing the microstructural transition at the supercritical region. Further, the solubility of 1-hexanol in aqueous micellar solution was found to increase as temperature and the number of hydrophilelipophile balance of surfactants increase.

• Bulletin of the Korean Chemical Society
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• 제32권8호
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• pp.2637-2642
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• 2011

A new ultrasonic-assisted micellar extraction and cloud-point pre-concentration method was developed for the determination of major saikosaponins, namely saikosaponins -A, -C and -D, in Radix Bupleuri by high performance liquid chromatography with evaporative light scattering detection (HPLC-ELSD). The non-ionic surfactant Genapol X-080 (oligoethylene glycol monoalkyl ether) was chosen as the extraction additive and parameters affecting the extraction efficiency were optimized. The highest yield was obtained with 10% (w/v) Genapol X-080, a liquid/solid ratio of 200:1 (mL/g) and ultrasonic-assisted extraction for 40 min. In addition, the optimum cloud-point pre-concentration was reached with 10% sodium sulfate and equilibration at $60^{\circ}C$ for 30 min. Separation was achieved on an Ascentis Express C18 column (100 ${\times}$ 4.6 mm i.d., 2.7 ${\mu}M$) using a binary mobile phase composed of 0.1% acetic acid and acetonitrile. Saikosaponins were detected by ELSD, which was operated at a $50^{\circ}C$ drift tube temperature and 3.0 bar nebulizer gas ($N_2$) pressure. The water-based solvent modified with Genapol X-080 showed better extraction efficiency compared to that of the conventional solvent methanol. Recovery of saikosaponins ranged from 93.1 to 101.9%. An environmentally-friendly extraction method was successfully applied to extract and enrich major saikosaponins in Radix Bupleuri.

• Bulletin of the Korean Chemical Society
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• 제24권9호
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• pp.1319-1323
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• 2003

This paper presents a successful demonstration of the on-line coupling of MEKC (micellar electrokinetic chromatography) to ESIMS (electrospray ionization mass spectrometry) for the quantitative analysis of seven s-triazine herbicides. The on-line MEKC-ESIMS was used to determine the structure of CE-separated peaks of seven triazine herbicides. The mixture of triazine herbicides was separated in a 20 mM sodium borate buffer (pH 8.5) containing 15 mM sodium dodecylsulfate (SDS) by using a bare fused-silica capillary. Electrospray ionization mass spectrometer was operated in the positive-ion mode when the mass spectra of seven triazine herbicides were observed from each peak, and the solution of water-methanol-formic acid (50/49/1 v/v/v) was used as a sheath liquid. The effects of SDS concentration, the run buffer pH, and the electric field on the separation of seven s-triazine herbicides were investigated. The MEKC-ESIMS detection showed 5 to 10 times higher sensitivity compared to the MEKC-UV detection. In addition, it did not need any pretreatment step.

• Journal of Ginseng Research
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• 제45권1호
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• pp.1-21
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• 2021

Panax species have gained numerous attentions because of their various biological effects on cardiovascular, kidney, reproductive diseases known for a long time. Recently, advanced analytical methods including thin layer chromatography, high-performance thin layer chromatography, gas chromatography, high-performance liquid chromatography, ultra-high performance liquid chromatography with tandem ultraviolet, diode array detector, evaporative light scattering detector, and mass detector, two-dimensional high-performance liquid chromatography, high speed counter-current chromatography, high speed centrifugal partition chromatography, micellar electrokinetic chromatography, high-performance anion-exchange chromatography, ambient ionization mass spectrometry, molecularly imprinted polymer, enzyme immunoassay, 1H-NMR, and infrared spectroscopy have been used to identify and evaluate chemical constituents in Panax species. Moreover, Soxhlet extraction, heat reflux extraction, ultrasonic extraction, solid phase extraction, microwave-assisted extraction, pressurized liquid extraction, enzyme-assisted extraction, acceleration solvent extraction, matrix solid phase dispersion extraction, and pulsed electric field are discussed. In this review, a total of 219 articles published from 1980 to 2018 are investigated. Panax species including P. notoginseng, P. quinquefolius, sand P. ginseng in the raw and processed forms from different parts, geographical origins, and growing times are studied. Furthermore, the potential biomarkers are screened through the previous articles. It is expected that the review can provide a fundamental for further studies.

• 약학회지
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• 제41권5호
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• pp.539-546
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• 1997

Capillary electrophoresis (CE) is perceived as an attractive tool for the analysis of pharmaceuticals and biological materials because of their high separation efficiency, easy separation and low running cost. New concept of micellar electrokinetic capillary chromatography (MECC) expanded the application of CE to the separation of neutral molecules. Validation of CE as an analytical technique for quality control of pharmaceuticals should be confirmed by quantitative analysis and the peak confirmation. In this study, the quantitative analyses of various types of neutral, acidic and basic components (acetaminophen, caffeine, ascorbic acid, riboflavin, thiamine, chlorpheniramine, phenylpropanolamine, dl-methylephedrine and dextromethorphan) in complex cold medicines have been accomplished using CE. Combined methods of MECC using SDS and capillary zone electrophoresis lowering the pH of running buffer were adopted to determine the ingredients in capsule type or liquid formula complex medicines without particular sample pretreatment. The results indicate that CE is a promising technique for quality control analysis of pharmaceuticals as a validation method.

• Bulletin of the Korean Chemical Society
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• 제13권3호
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• pp.240-245
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• 1992

The effect of the addition of sodium dodecyl sulfate (SDS) to a buffered mobile phase (pH 3.4) on the retention of nucleotides, nucleosides and bases was investigated with a polyvinyl alcohol (PVA) column. Depending on the concentration of SDS, two different trends in the retention of nucleosides and bases containing an $NH_2$ group were observed. If the concentration of SDS was less than 5.5 mM, the retention of compounds containing an $NH_2$ group increased as the concentration of SDS in the mobile phase increased. In contrast, if the concentration was greater than 5.5 mM, the retention of compounds containing an $NH_2$ group decreased. Thus, the SDS acted as an ion-pairing reagent at lower concentration but formed micelles at higher concentrations. The retention behavior of the nucleosides and bases in the presence of a micellar concentration of SDS in the mobile phase on the PVA column was compared to the retention behavior on other types of columns.