Retention and separation factors of enantiomers of several dipeptides were measured on chiral stationary phases with grafted macrocyclic antibiotic ristocetin A from different manufacturers, Chirobiotic R and Nautilus-R, using buffered and unbuffered methanol–water mixtures with 0 to 90% (v/v) of methanol as mobile phases. A remarkable difference in enantioselectivity toward both hydrophilic and hydrophobic dipeptides was observed between these two stationary phases that were explained by different configurations of the binding sites of the selectors resulted from different anchoring reactions applied to graft the antibiotic moiety to the silica support and also by different number of ionizable amino groups of the grafted selectors.

中文翻译：

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具有接枝抗生素瑞斯托菌素 A 的两个手性固定相的对映选择性的异常差异

使用来自不同制造商 Chirobiotic R 和 Nautilus-R 的接枝大环抗生素瑞斯托菌素 A 的手性固定相，使用 0 至 90% (v/v) 的缓冲和非缓冲甲醇-水混合物，测量了几种二肽对映体的保留和分离因子甲醇作为流动相。在这两种固定相之间观察到对亲水性和疏水性二肽的对映选择性的显着差异，这是由于选择剂结合位点的不同构型是由于将抗生素部分接枝到二氧化硅载体上的不同锚定反应以及不同的接枝选择器的可电离氨基的数量。