大體積進樣之毛細管電泳法的開發與研究

Abstract

為了更加提高毛細管電泳法的偵測靈敏度，本研究開發出兩種線上濃縮技術，分別為大小管結合線上掃集法（Coupled-capillary/ sweeping-MEKC, CC/sweeping-MEKC）及整管進樣堆積結合線上掃集法（Full-capillary sample stacking/sweeping-MEKC, FCSS/sweeping- MEKC）。在大小管結合線上掃集方法中，藉由管徑較大部分為進樣端，樣品進樣量可達1.8 L。其中，因為毛細管大小內徑的不均等，會造成電場的不均勻性（大管徑部分：低場強；小管徑部分：高場強）。當SDS微胞在大管徑部分進行掃集時，由於電場不均勻性的影響下，使分析物以非常緩慢的速率逐漸被微胞掃集起來，因此可進一步增加濃縮效率。另一方面，整管進樣堆積結合線上掃集法結合了stacking、sweeping、dynamic pH-junction、MEKC四種技術，而達成整管樣品進樣（最大體積）之目的，其中樣品進樣量可達2.7 L。與MEKC做比較，以上兩種方法在偵測靈敏度上分別有500倍及350倍的改進效果。In an attempt to improve the sensitivity of detection in capillary electrophoresis, two novel online sample concentration methods were developed, coupled-capillary/sweeping-MEKC (CC/sweeping-MEKC) and full-capillary sample stacking/sweeping-MEKC (FCSS/sweeping- MEKC). In the former case, compared to a single capillary, a larger volume of sample solution can be injected (up to 1.8 L), since the ID of capillary used is wider. Furthermore, when the coupled-capillary is used, an unequal-electric field (wide portion: lower field strength; narrow portion: higher field strength) along with the capillary axis is created. When the SDS micelles passed through the coupled-capillary, the analytes are gradually and slowly swept to the wide portion. Hence, the analytes can be swept more efficiency. In the latter case, four techniques, including stacking, dynamic pH-junction, sweeping, MEKC, were combined to acquire a larger sample injection. As a result, a full column injection could be achieved (up to 2.7 L). Compared to the normal MEKC mode, the limit of detection can be improved by 500- and 350-fold, respectively, when the CC/sweeping-MEKC and FCSS/ sweeping-MEKC methods are applied.