Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, Canada V6T 1Z1.
Anal Chem. 2011 Jun 15;83(12):4916-23. doi: 10.1021/ac200636y. Epub 2011 May 17.
When coupling capillary electrophoresis with postcolumn detection methods, such as mass spectrometry, the presence of postcolumn band broadening must be considered. The band broadening effects introduced by junction-at-the-tip CE-MS interfaces using a postcolumn micro flow-through vial are investigated by studying the hydrodynamic flow patterns and mass transport process inside the micro vial at the end of the CE separation capillary. Simulation results obtained by solving the Navier-Stokes and mass balance equations provide insights into the velocity field and concentration distribution of the analytes in the micro vial and demonstrate that, with a low flow rate of chemical modifier solution, the laminar flow streams confine the analyte molecules to the central part of the micro vial and thus maintain major features of the peak shapes. Peaks detected by UV and MS under similar experimental conditions were compared to verify the numerical prediction that the main features of the UV peak can be retained in the MS peak. Experiments also show that band broadening can be minimized when an appropriate chemical modifier flow rate is selected.
当将毛细管电泳与柱后检测方法（如质谱法）相结合时，必须考虑柱后带宽展宽的问题。通过研究 CE 分离毛细管末端的柱后微流通池内的流体动力学流动模式和传质过程，研究了在尖端连接的 CE-MS 接口中使用柱后微流通池引入的带宽展宽效应。通过求解纳维-斯托克斯方程和质量平衡方程获得的模拟结果深入了解了微池内分析物的速度场和浓度分布，并表明在化学修饰剂溶液的低流速下，层流流体会将分析物分子限制在微池的中心部分，从而保持峰形的主要特征。在相似的实验条件下，比较了通过 UV 和 MS 检测到的峰，以验证数值预测，即 MS 峰可以保留 UV 峰的主要特征。实验还表明，当选择适当的化学修饰剂流速时，可以最小化带宽展宽。
