本實驗利用毛細管膠束電泳在低pH值的環境下，以陰離子型界面活性劑SDS分離16種 EPA多環芳香烴(polycyclic aromatic hydrocarbons, PAHs)。PAHs為一系列疏水性的多苯環分子，能與界面活性劑長碳鏈行疏水性作用，在高電場中向陽極泳動。PAHs被SDS帶動的電泳遷移率大小與其分子量、構型、以及疏水性質有關。在低pH值條件下毛細管的電滲透流會被抑制，PAHs的分離解析效果主要是依據PAHs分子和SDS分子交互作用所產生的電泳遷移率差異性大小。我們藉由改變緩衝溶液的有機溶劑組成，及添加不同種類的添加物，來研究分離PAHs的最佳條件。在固定SDS濃度，改變有機溶劑(CH3OH和CH3CN)組成的實驗中，我們發現，較高極性的緩衝溶液有助於小環分子(2~4環)的分離，但五環以上的PAHs則要在較低極性環境中才有較佳分離效果。添加不同高分子和不同類型的界面活性劑，可當作除了SDS外的另一擬固定相，並可修飾毛細管壁，以增加PAHs的分離解析度。 In this experiment we used SDS micellar electrokinetic capillary chromatography to separate 16 EPA priority PAHs (polycyclic aromatic hydrocarbons) in low pH buffer. PAHs are a series of hydrophobic molecules having multiple fused benzene-ring structure. They can undergo hydrophobic interactions with the long carbon chains of the anionic surfactant molecules, and thus migrate toward anode under the applied high voltage. The electrophoretic mobilities of the SDS-carried PAHs are related to some PAHs properties such as molecular weight, molecular conformation, and hydrophobicity. The electroosmotic flow of capillary column could be suppressed when low pH buffer was used. Therefore, the separation resolution of PAHs would mainly depend on the differences in their electrophoretic mobilities caused by the hydrophobic interaction between PAHs and SDS. In order to study the optimized conditions for separating PAHs, different organic solvents and additives were added into run buffer to increase the mobility differences among the 16 PAHs. In the experiment of fixing SDS concentrations and changing the compositions of organic solvents, CH3OH and CH3CN, we found that PAHs with less than 4 benzene rings could be better resolved in buffers with higher polarity. On the other hand, PAHs with more than 5 benzene rings would be better resolved in less polar buffers. In addition to SDS, we also added different polymers and surfactants into the buffer solutions to provide another pseudo stationary phase, and to modify the inner wall of capillary for increasing the separation resolution of PAHs.