title: Micelle-mediated extraction and cloud point preconcentration for the analysis of aesculin and aesculetin in Cortex fraxini by HPLC.
abstract: In this paper, a micelle-mediated extraction and cloud point preconcentration method was developed for the determination of less hydrophobic compounds aesculin and aesculetin in Cortex fraxini by HPLC. Non-ionic surfactant oligoethylene glycol monoalkyl ether (Genapol X-080) was employed as the extraction solvent. Various experimental conditions were investigated to optimize the extraction process. Under optimum conditions, i.e. 5% Genapol X-080 (w/v), pH 1.0, liquid/solid ratio of 400:1 (ml/g), ultrasonic-assisted extraction for 30 min, the extraction yield reached the highest value. For the preconcentration of aesculin and aesculetin by cloud point extraction (CPE), the solution was incubated in a thermostatic water bath at 55 degrees C for 30 min, and 20% NaCl (w/v) was added to the solution to facilitate the phase separation and increase the preconcentration factor during the CPE process. Compared with methanol, which was used in Chinese Pharmacopoeia (2005 edition) for the extraction of C. fraxini, the extraction efficiency of 5% Genapol X-080 reached higher value.
authors.affiliation: College of Chemistry and Environmental Science, Hebei University, Baoding 071002, China. shizhihong@mail.hbu.edu.cn
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Shi
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Zhu
authors.forename: Hongyi
authors.initials: H
authors.lastname: Zhang
mesh_terms: D031319:Aesculus; D002851:Chromatography, High Pressure Liquid; D004365:Drugs, Chinese Herbal / Q000032:analysis*; D004573:Electrolytes / Q000737:chemistry; D004929:Esculin / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D008823:Micelles; D011208:Powders / Q000032:analysis; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet; D013501:Surface-Active Agents / Q000737:chemistry; D013696:Temperature; D014468:Umbelliferones / Q000032:analysis*
chemical_list: D004365:Drugs, Chinese Herbal; D004573:Electrolytes; D007202:Indicators and Reagents; D008823:Micelles; D011208:Powders; D013501:Surface-Active Agents; D014468:Umbelliferones; D004929:Esculin; C517354:horse chestnut seed; C007628:esculetin