毛细管电泳流动注射-负压进样装置的研究

Study of Flow Injection-Negatively Pressurized Sampling Equipment in Capillary Electrophoresis

设计了一种用于毛细管电泳系统的流动注射-负压进样装置。样品由蠕动泵输送到进样阀后再由缓冲液带到分离毛细管入口,由毛细管出口端施加的负压引入。进样时间由自制精密控时电路控制,经进样条件的优化,能获得良好的重现性。实验中两种阳离子峰面积和迁移时间的RSD(n=8)≤2.7%,优于传统重力进样,而且操作简便;与非接触电导检测器组装成流动注射-毛细管电泳系统,可实现快速、高效的在线分析。初步应用于无机阳离子的分离,取得了满意的结果。

A flow injection-negatively pressurized sampling （FI-NPS） equipment was designed. The sample was carried to the injection valve by a peristaltic pump and carried to the inlet of separation capillary by buffer solution, then sample injection into capillary was performed through the negative pressure set in the outlet of capillary. Duration of injection was controlled by a home-made precise time circuit. With the optimization of the injection parameters, better repeatability and simple operation have been achieved. The RSD values of peak area and migration time for two selected cations （ Na^＋ and K^＋ ） were within the range of 0.7%～2.7% using this injection method. A rapid and efficient on-line analysis could be carried out in the CE system coupling with this equipment and contactless conductivity detector （CCD）. In the application to the inorganic cation separation, satisfactory results that the performance of sampling and baseline separation of six cations has been achieved in less than 10 min were observed.