Abstract The adsorption of mandelic acid enantiomers on the Nautilus-E chiral stationary phase with eremomycin as a grafted antibiotic, as affected by value of the water-ethanol eluent under conditions of an overloaded column, was studied. Adsorption equilibrium under experimental conditions, when mandelic acid dissociates both completely and then very weakly, was studied. The adsorption isotherms of S- and R-mandelic acid were plotted by the Glueckauf method and inverse method using bi-Langmuir model, as well as the tri-Langmuir model assuming independent adsorption on three types of adsorption centers, with two of them being high-energy enantioselective (ion-exchange and molecular adsorption) and the third – the low-energy nonselective types of sites. This model takes into account the ionization of mandelic acid in the eluent and a change in the value in the mass transfer zone caused by its ionization. The saturated capacity and binding energy of all the types of adsorption sites depend on of the eluent. Nonselective interactions contribute to the adsorption of mandelic acid mainly. To determine the adsorption isotherms of mandelic acid enantiomers on Nautilus-E CSP in the absence of its dissociation and distortion of the elution profiles, the Glueckauf method and the bi-Langmuir model were identified as an acceptable choice. Graphical Abstract

中文翻译：

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扁桃酸对映体在接枝抗生素埃雷霉素手性固定相上的吸附：洗脱液 pH 值的影响

摘要 研究了在过载色谱柱条件下受水-乙醇洗脱液值影响的扁桃酸对映体在以埃雷霉素为接枝抗生素的鹦鹉螺-E 手性固定相上的吸附。研究了实验条件下的吸附平衡，当扁桃酸既完全离解又非常微弱离解时。S-和R-扁桃酸的吸附等温线通过Glueckauf方法和使用bi-Langmuir模型的逆方法以及假设在三种类型的吸附中心上独立吸附的tri-Langmuir模型绘制，其中两种吸附中心为高-能量对映选择性（离子交换和分子吸附）和第三个 - 低能量非选择性类型的位点。该模型考虑了洗脱液中扁桃酸的电离以及由其电离引起的传质区值的变化。所有类型吸附位点的饱和容量和结合能取决于洗脱液。非选择性相互作用主要有助于扁桃酸的吸附。为了确定扁桃酸对映异构体在 Nautilus-E CSP 上没有解离和洗脱曲线失真的情况下的吸附等温线，Glueckauf 方法和 bi-Langmuir 模型被确定为可接受的选择。图形概要 为了确定扁桃酸对映异构体在 Nautilus-E CSP 上没有解离和洗脱曲线失真的情况下的吸附等温线，Glueckauf 方法和 bi-Langmuir 模型被确定为可接受的选择。图形概要 为了确定扁桃酸对映异构体在 Nautilus-E CSP 上没有解离和洗脱曲线失真的情况下的吸附等温线，Glueckauf 方法和 bi-Langmuir 模型被确定为可接受的选择。图形概要