Influence of organic modifier concentration on plate number in micellar electrokinetic chromatography. 1. 2-propanol.
Influence of organic modifier concentration on plate number in micellar electrokinetic chromatography. 1. 2-propanol.
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有机改性剂浓度对胶束电动色谱中塔板数的影响。
DOI：
10.1021/ac980417b
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发表时间：
1998
影响因子：
7.4
通讯作者：
Stevens,WC
中科院分区：
文献类型：
--
作者：
Seals,TH;Davis,JM;Murphy,MR;Smith,KW;Stevens,WC
本文建立了十二烷基硫酸钠(十二烷基硫酸钠)和异丙醇(2PN)缓冲溶液中胶束电动色谱效率损失的物理化学基础。弱保留、中等保留和强保留分析物在含有50 mM十二烷基硫酸钠和体积为0-10%2PN的磷酸盐/硼酸盐缓冲液中分离。它们的板块数与基于纵向扩散和对弥散的工具贡献的理论的预测大体一致。在此浓度范围内，2PN对弱保留和中等保留分析物的影响不大，因为它们的扩散系数与缓冲液粘度成反比，保留时间与粘度成正比。这些对扩散的综合影响几乎被抵消了。然而，强保留分析物的则随2Pn的增加而减小，因为它们的扩散系数与粘度成反比，但它们的保留时间比粘度增加得更快。这些对分散的综合影响并没有抵消。这些差异的产生是因为2PN穿透了胶束，导致结合的反离子释放，增加了胶束电荷和电泳迁移率。随着2PN浓度的增加，胶束对电渗流的电泳化速度越来越快。因此，保留较强的化合物需要越来越长的时间才能洗脱。
This paper establishes a physicochemical basis for the efficiency losses in micellar electrokinetic chromatography in buffers containing sodium dodecyl sulfate (SDS) and 2-propanol (2PN). Weakly, intermediately, and strongly retained analytes were separated in phosphate/borate buffers containing 50 mM SDS and from 0 to 10% 2PN by volume. Their plate numbersNgenerally agreed well with predictions of a theory forNbased on longitudinal diffusion and instrumental contributions to dispersion. TheN's of weakly and intermediately retained analytes were not affected strongly by 2PN over this concentration range, because their diffusion coefficients varied inversely with buffer viscosity and their retention times largely varied directly with viscosity. These combined effects on dispersion almost canceled. However, theN's of strongly retained analytes decreased with increasing 2PN, because their diffusion coefficients varied inversely with viscosity but their retention times increased more rapidly than did viscosity. These combined effects on dispersion did not cancel. These differences occurred because 2PN penetrated the micelles, caused bound counterions to be released, and increased the micellar charge and electrophoretic mobility. As 2PN concentration increased, the micelles electrophoresced increasingly rapidly against the electroosmotic flow. Consequently, strongly retained compounds required increasingly long times to elute.