Schmitt Ulrich, Ertan Mevlut, Holzgrabe Ulrike
Institute of Pharmacy and Food Chemistry, University of Würzburg, Würzburg, Germany.
Electrophoresis. 2004 Aug;25(16):2801-7. doi: 10.1002/elps.200405932.
Comparative enantioseparation of the enantiomers of 1,1'-binaphthyl-2,2'-diyl hydrogen phosphate was performed with cyclodextrin (CD)-modified capillary electrophoresis (CE). Two single isomers, beta-CD, heptakis(2,3,6-tri-O-methyl)-beta-CD (TM-beta-CD), and heptakis(2,6-di-O-methyl)-beta-CD (DM-beta-CD) of 98% purity as well as heptakis(2,3-di-O-acetyl)-beta-CD were used and compared in terms of resolution power to randomly methylated and corresponding acetylated beta-CDs, which were synthesized in our laboratory. The methylated ones were characterized by means of matrix-assisted laser desorption/ionization-time of flight-(MALDI-TOF) mass spectrometry. By testing defined mixtures of single isomers and comparing their resolution power to randomly substituted CDs of similar degree of substitution we could show, that a simple characterization by the average molecular degree of substitution (DS) is not sufficient. In order to get reproducible results, a clearly defined substitution pattern is necessary, which is not given using randomly substituted CDs. Taken together, a validation of a chiral separation with "undefined" CD derivatives is almost impossible.
采用环糊精（CD）修饰的毛细管电泳（CE）对1,1'-联萘-2,2'-二磷酸酯对映体进行了对映体拆分。使用了两种纯度为98%的单一异构体，即β-环糊精、七（2,3,6-三-O-甲基）-β-环糊精（TM-β-CD）和七（2,6-二-O-甲基）-β-环糊精（DM-β-CD），以及七（2,3-二-O-乙酰基）-β-环糊精，并就分离能力与我们实验室合成的随机甲基化和相应乙酰化的β-环糊精进行了比较。甲基化产物通过基质辅助激光解吸/电离飞行时间（MALDI-TOF）质谱进行表征。通过测试单一异构体的特定混合物，并将其分离能力与取代度相似的随机取代环糊精进行比较，我们发现，仅通过平均分子取代度（DS）进行简单表征是不够的。为了获得可重复的结果，需要一个明确界定的取代模式，而随机取代的环糊精无法提供这样的模式。总之，使用“未定义”的环糊精衍生物进行手性分离的验证几乎是不可能的。
