Providing Enhanced Migration Time Reproducibility with a High-Voltage-Compatible Flow Sensor for Capillary Electrophoresis

In capillary electrophoresis (CE), analyte identification is primarily based on migration time, which is a function of the analyte’s electrophoretic mobility and the electro-osmotic flow (EOF). The migration time can be impacted by the presence of parasitic flow from changes in temperature or pressure during the run. Presented here is a high-voltage-compatible flow sensor capable of monitoring the volumetric flow inside the capillary during a separation with nL/min resolution. The direct measurement of both flow and time allows for compensation of flow instabilities. By expressing the electropherogram in terms of signal versus electromigration velocity instead of time, it is possible to improve the run-to-run reproducibility up to 25×.在毛细管电泳（CE）中，分析物鉴定主要基于迁移时间，而迁移时间是分析物电泳迁移率与电渗流（EOF）的函数。运行过程中温度或压力变化引发的寄生流会对迁移时间产生影响。本文介绍了一款高压兼容型流量传感器，可在分离过程中监测毛细管内的体积流量，分辨率达纳升每分钟（nL/min）级别。通过同时对流量与时间进行直接测量，能够实现流量不稳定性的补偿。若将电泳谱图以信号对电迁移速度而非时间进行表征，可将批间重现性提升最高达25倍。