Benavente Fernando, Balaguer Elvira, Barbosa José, Sanz-Nebot Victoria
Department of Analytical Chemistry, University of Barcelona, Diagonal 647, 08028 Barcelona, Spain.
J Chromatogr A. 2006 Jun 2;1117(1):94-102. doi: 10.1016/j.chroma.2006.03.049. Epub 2006 Apr 17.
The applicability in capillary electrophoresis-electrospray mass spectrometry (CE-ESI-MS) of the classical semiempirical relationships between electrophoretic mobility and charge-to-mass ratio (me versus q/Malpha) has been investigated in order to describe the migration behavior of a series of bioactive peptide hormones. The influence upon the models of the separation electrolyte pH and the accuracy of the pK values of these compounds were studied first by capillary electrophoresis with ultraviolet detection (CE-UV). The classical polymer model, alpha = 1/2, resulted in slightly better correlations at any of the studied pH. Furthermore, a general linear equation can be adjusted combining all the experimental data pairs, which suggests that correlation in the whole pH range is independent of the ionic form of the studied peptide hormones. The plots of q/M1/2 against separation electrolyte pH were used to predict their electrophoretic separations, using the accurate pK values obtained in a previous work by CE-UV for charge calculations. A volatile separation electrolyte containing 50 mM of acetic acid and 50 mM of formic acid at pH 2.85 was selected for optimum CE-UV and CE-ESI-MS analysis of the peptide mixture. At this pH and taking into account the specific features of the coupling, the correlation using the classical polymer law was excellent and its parameters were similar to the ones of the general linear equation previously obtained by CE-UV. This confirmed the applicability in CE-ESI-MS of the semiempirical relationship originally established by CE-UV.
为了描述一系列生物活性肽激素的迁移行为，研究了电泳淌度与质荷比之间的经典半经验关系（(m_e) 与 (q/M^\alpha)）在毛细管电泳 - 电喷雾质谱（CE - ESI - MS）中的适用性。首先通过紫外检测毛细管电泳（CE - UV）研究了分离电解质pH值和这些化合物 (pK) 值的准确性对模型的影响。经典聚合物模型 (\alpha = 1/2) 在任何研究的pH值下都产生了稍好的相关性。此外，可以调整一个通用线性方程来组合所有实验数据对，这表明在整个pH范围内的相关性与所研究肽激素的离子形式无关。利用CE - UV在先前工作中获得的准确 (pK) 值进行电荷计算，绘制 (q/M^{1/2}) 对分离电解质pH值的曲线来预测它们的电泳分离。选择了一种在pH 2.85时含有50 mM乙酸和50 mM甲酸的挥发性分离电解质，用于肽混合物的最佳CE - UV和CE - ESI - MS分析。在此pH值下，并考虑到耦合的具体特征，使用经典聚合物定律的相关性非常好，其参数与先前通过CE - UV获得的通用线性方程的参数相似。这证实了最初由CE - UV建立的半经验关系在CE - ESI - MS中的适用性。
