Wistuba Dorothee, Trapp Oliver, Gel-Moreto Nuria, Galensa Rudolf, Schurig Volker
Institut für Organische Chemie, Universität Tübingen, 72076 Tübingen, Germany.
Anal Chem. 2006 May 15;78(10):3424-33. doi: 10.1021/ac0600499.
The stereoisomeric separation of several flavanones and flavanone-7-O-glycosides has been achieved with capillary electrophoresis by adding native cyclodextrins or cyclodextrin derivatives to the background electrolyte. As an alternative method, micellar electrokinetic chromatography with sodium cholate as a chiral surfactant has been used for the epimeric separation of two flavanone-7-O-glycosides. The effect of buffer systems containing mixtures of cyclodextrin with either sodium dodecyl sulfate or sodium cholate upon the chiral recognition of flavanones and flavanone-7-O-glycosides as well as the variation of the background electrolyte (concentration of buffer and surfactant, pH value, organic modifier), and its influence on the resolution factor Rs was investigated. Temperature- and pH-dependent enantiomerization or epimerization barriers of several flavanones (naringenin, homoeriodictyol) and flavanone-7-O-glycosides (naringin, neohesperidin, prunin, narirutin) in basic media (pH values of 9-11) have been observed. Interconversion profiles featuring characteristic plateau formation of the elution pattern were observed at high pH and evaluated with the simulation software ChromWin to determine rate constants k(T) and Eyring activation parameters, DeltaG#(T), DeltaH#, and DeltaS#.
通过向背景电解质中添加天然环糊精或环糊精衍生物，利用毛细管电泳实现了几种黄烷酮和黄烷酮 -7-O-糖苷的立体异构体分离。作为一种替代方法，以胆酸钠作为手性表面活性剂的胶束电动色谱法已用于两种黄烷酮 -7-O-糖苷的差向异构体分离。研究了含有环糊精与十二烷基硫酸钠或胆酸钠混合物的缓冲系统对黄烷酮和黄烷酮 -7-O-糖苷的手性识别的影响，以及背景电解质的变化（缓冲液和表面活性剂的浓度、pH值、有机改性剂）及其对分离因子Rs的影响。在碱性介质（pH值为9 - 11）中观察到了几种黄烷酮（柚皮素、高圣草酚）和黄烷酮 -7-O-糖苷（柚皮苷、新橙皮苷、樱草糖苷、橙皮芸香苷）的温度和pH依赖性对映体异构化或差向异构化屏障。在高pH下观察到了具有洗脱模式特征性平台形成的互变曲线，并使用模拟软件ChromWin进行评估，以确定速率常数k(T)和艾林活化参数ΔG#(T)、ΔH#和ΔS#。
