陽離子溶質與十二烷基硫酸鈉鹽之相互作用對影響微胞形成及臨界微胞濃度之毛細管電泳研究

Capillary Electrophoretic Studies on Influence of Interactions of Cationic Solutes with Sodium Dodecyl Sulfate on the Formation of Micelles and its Critical Micelle Concentration

方怡茹(I-Ju Fang)

指導教授 ： 林敬二

國立臺灣大學/理學院/化學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.00727

摘要

本論文第一部份是利用毛細管電泳法在pH 6及pH 7下，選用帶正電荷的茶酚胺(catecholamine)及結構相似的化合物做為探測物質，探討溶質的遷移行為及陽離子溶質與十二烷基硫酸鈉鹽（Sodium Dodecyl Sulfate，SDS）的交互作用如何影響微胞形成及SDS的臨界微胞濃度（critical micelle concentration，CMC）。由於溶質性質和SDS之間涉及了不同程度的氫鍵、疏水性和離子作用，測出的CMC值會有所不同。
我們利用三種方法分析實驗數據，得到不同的CMC值。當SDS濃度增加時，溶質的電泳遷移率及滯留因子會隨之變化。所以分析溶質的電泳遷移率及滯留因子的變化趨勢，可獲知關於CMC值的資訊。另外，滯留因子與分配係數及分配比之間存在的線性關係同樣也能求出CMC值。這些方法的適宜性將在文中被討論。
雖然陽離子溶質與SDS形成的離子對有助於微胞形成。但兩者之間的氫鍵作用會弱化此吸引力，造成CMC值大幅度上升。所以，由茶酚胺求得的CMC值會比其他化合物大。同時我們也會討論樣品基質中甲醇含量的影響。
第二部分是利用毛細管電泳法在pH 7.0的條件下，選用帶正電荷的溶質為分析物，探討

關鍵字

臨界微胞濃度

並列摘要

Abstract
The migration behavior of cationic solutes and influences of the interactions of cationic solutes with sodium dodecyl sulfate (SDS) on the formation of micelles and its critical micelle concentration (CMC) were investigated by capillary electrophoresis at neutral/acidic pH. Catecholamines and structurally related compounds, including epinephrine, norepinephrine, dopamine, norephedrine, and tyramine, which involve different extents of hydrophobic, ionic and hydrogen bonding interactions with SDS surfactant, are selected as cationic solutes. The dependence of the effective electrophoretic mobility of cationic solutes on the concentration of SDS monomers in the premicellar region provides direct evidence of the formation of ion-pairs between cationic solutes and SDS monomers. Three different approaches, based on the variations of either the effective electrophoretic mobility or the retention factor as a function of SDS concentration in the premicellar and micellar regions, and the linear relationship between the retention factor and the product of a distribution coefficient and the phase ratio, were considered to determine the CMC value of SDS micelles. The suitability of the methods used for the determination of the CMC of SDS with these cationic solutes was discussed. Depending on the structures of cationic solutes and electrophoretic conditions, the CMC value of SDS determined varies in a wide concentration range. The results indicate that, in addition to hydrophobic interaction, both ionic and hydrogen bonding interactions have pronounced effects on the formation of SDS micelles. Ionic interaction between cationic solutes and SDS surfactant stabilizes the SDS micelles, whereas hydrogen bonding interactions weakens the solubilization of the attractive ionic interaction. The elevation of the CMC of SDS depends heavily on hydrogen bonding interactions between cationic solutes and SDS surfactant. Thus the CMC value of SDS is remarkably elevated with catecholamines, such as epinephrine and norepinephrine, as compared with norephedrine. In addition, the effect of methanol content in the sample solution of these cationic solutes on the CMC of SDS was also examined. The binding constant of cationic solutes with SDS monomers and those of cationic solutes to SDS micelles are evaluated.
The influence of

並列關鍵字

cationic solutes ,critical micelle concentration

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