N-Propyl-N&-2-pyridylurea-modified silica as mixed-mode stationary phase with moderate weak anion exchange capacity and pH-dependent surface charge reversal
N-Propyl-N&-2-pyridylurea-modified silica as mixed-mode stationary phase with moderate weak anion exchange capacity and pH-dependent surface charge reversal
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DOI：
10.1016/j.chroma.2018.05.012
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发表时间：
2018-07-27
影响因子：
4.1
通讯作者：
Laemmerhofer, Michael
中科院分区：
文献类型：
--
作者：
Baeurer, Stefanie;Polnick, Stefan;Laemmerhofer, Michael
在此，我们提出了一种新型的用N-丙基-N '-2-吡啶基脲选择剂修饰的硅胶基固定相。由于吡啶选择剂的弱碱性和选择剂固定化后残留硅烷醇的存在，在约pH 5.5下观察到的具有pl的两性离子表面通过电泳光散射在pH依赖性zeta电位测定中测量。研究了新型N-丙基-N '-2-吡啶脲改性硅胶作为混合模式固定相的性能。为此目的，其特征在于RP和HILIC条件下使用测试混合物。通过色谱试验所得保留因子的主成分分析，对该固定相与内部和商业基准进行了后续分类。结果表明，一个相对独特的混合模式字符之间的测试固定相。酸性化合物的色谱保留特性与zeta电位测定结果吻合良好。在低pH值（例如pH 5）下的阴离子交换和在pH 7下的离子排斥色谱用于分离尿苷5 '-单磷酸、二磷酸和三磷酸的应用证明了固定相表面的pH依赖性Umpolung。这些分离原理在pH梯度从5到7的组合产生了弱的阴离子交换选择性与电荷诱导的洗脱由于在较高的pH值的排斥相互作用，并导致在温和的洗脱条件下，在一个显着更快的分离与改进的峰形。(C)2018爱思唯尔B. V.保留所有权利。
Herein, we present a novel silica-based stationary phase modified with N-propyl-N'-2-pyridylurea selector. Due to the weakly basic properties of the pyridine selector and the presence of residual silanols after selector immobilization, a zwitterionic surface with a pl observed at approximately pH 5.5 was measured by electrophoretic light scattering in pH-dependent zeta-potential determinations. The capability of the new N-propyl-N'-2-pyridylurea-modified silica to serve as mixed-mode stationary phase was investigated. For this purpose, it was characterized under RP and HILIC conditions using test mixtures. Subsequent classification of this stationary phase in comparison to in-house and commercial benchmarks was carried by principal component analysis of resultant retention factors from chromatographic tests. The results show a relatively unique mixed-mode character amongst the tested stationary phases. The chromatographic retention characteristics of acidic compounds matched well the zeta-potential determinations. The application of anion-exchange at low pH values (e.g. pH 5) and ion exclusion chromatography at pH 7 for the separation of uridine 5'-mono-, di- and triphosphate demonstrated a pH-dependent umpolung of the stationary phase surface. The combination of these separation principles in a pH gradient from 5 to 7 gave rise to weak anion-exchange selectivity with a charge-inducted elution due to repulsive interactions at higher pH and resulted in a significant faster separation with improved peak shape under mild elution conditions. (C) 2018 Elsevier B.V. All rights reserved.