Diffusivity of solutes measured in glass capillaries using Taylor's analysis of dispersion and a commercial CE instrument
Diffusivity of solutes measured in glass capillaries using Taylor's analysis of dispersion and a commercial CE instrument
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DOI：
10.1021/ac048846z
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发表时间：
2005-02-01
影响因子：
7.4
通讯作者：
Carbeck, JD
中科院分区：
文献类型：
--
作者：
Sharma, U;Gleason, NJ;Carbeck, JD
我们提出了一种使用商用毛细管电泳 (CE) 仪器快速、高效和准确测量溶质扩散系数 (D) 的策略。该方法利用了 Taylor（Taylor, G. I. Proc. R. Soc. London, Ser. A 1953, 219, 186-203）对通过玻璃毛细管静压泵送的溶质分散体的经典分析。为了获得准确的 D 值，我们修改了泰勒的色散分析，以考虑使用 CE 仪器时在毛细管中达到稳态流动所需的有限时间。忽略这种效应会导致模型溶质苯丙氨酸的测量扩散率与公布的值相比误差高达 60%。我们提供了对此影响的分析以及避免这些错误的简单策略。使用这种方法，我们分析了苯丙氨酸浓度前沿和 D 测量值的分布，与已发布值的误差在 5% 以内。我们还分析了溶质脉冲的分布。为了准确确定 D 值，首先需要根据注入体积对分散度进行测量，以校正注入塞的有限宽度，然后再针对非稳态流动进行校正。该方法还得出苯丙氨酸的 D 值，与已发布值的误差在 5% 以内。与用于测定 D 的其他技术相比，该方法不需要荧光标记，并且适用于任何分子量的溶质。
We present a strategy for the rapid, efficient, and accurate measurement of the coefficient of diffusion (D) of solutes using a commercial capillary electrophoresis (CE) instrument. This approach utilizes the classic analysis of Taylor (Taylor, G. I. Proc. R. Soc. London, Ser. A 1953, 219, 186-203) of the dispersion of solutes pumped hydrostatically through glass capillaries. To obtain accurate values of D, we modified Taylor's analysis of dispersion to account for the finite time required to reach steady-state flow in the capillary when using a CE instrument. Neglecting this effect results in measured diffusivities of phenylalanine, a model solute, that are in error by as much as 60% when compared with published values. We provide an analysis of this effect and a simple strategy for avoiding these errors. Using this approach, we analyze profiles of concentration fronts and measured values of D for phenylalanine to within 5% of published values. We also analyze profiles of pulses of solute. To determine values of D accurately, measurements of dispersion first need to be made as a function of injection volume to correct for the finite width of the injection plug, before they are corrected for unsteady-state flow. This approach also yields values of D for phenylalanine to within 5% of published values. In contrast to other techniques used for the determination of D, this approach requires no fluorescent labeling and is applicable to solutes of any molecular weight.