以毛細管電泳法計算主-客內包錯合物結合常數之研究; Application of cyclodextrin-mediated capillary electrophoresis to determine the apparent binding constants and of the alkylnaphthalene derivatives

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題名:	以毛細管電泳法計算主-客內包錯合物結合常數之研究;Application of cyclodextrin-mediated capillary electrophoresis to determine the apparent binding constants and of the alkylnaphthalene derivatives
作者:	吳斯燻;Szu-Hsun Wu
貢獻者:	化學研究所
關鍵詞:	環糊精;毛細管電泳法;結合常數;熱力學;Inclusion complex;Cyclodextrins;Thermodynamic parameters;Apparent binding constants
日期:	2005-06-01
上傳時間:	2009-09-22 10:13:29 (UTC+8)
出版者:	國立中央大學圖書館
摘要:	毛細管電泳層析術提供了極高效率的分離度，且分析速度快、以及具有分析少量樣品和溶劑消耗量少的特性，並且可以使用多種分離模式針對大部分的物質進行電泳分離。藉由添加一種具有空腔結構的主分子與分析物 (客分子)錯合形成非共價鍵錯合物（non-covalent bond complex），而形成非共價鍵結構的主-客錯合物（host-guest complexes）或稱為內包錯合物（inclusion complexes），進而影響內包錯合物之電泳遷移率，以達到結構異構物及藥物之光學異構物分離（chiral separation）。毛細管電泳的應用於生物分子辨識 (molecular recognition)之研究多用來鑑定抗原－抗體或受質（ligand）－受器（receptor）間之作用力的專一性，藉由簡化的主-客模型來預測複雜的自然生物行為，而毛細管電泳不僅可從事這些作用力的定性分析研究，同時亦適合於定量上的探討。在適當的條件下，毛細管環糊精修飾區帶電泳法 (cyclodextrin electrokinetic chromatography, CD-EKC)能有效分離七種中性烷基?環分子位置異構物，分離的最佳條件是在緩衝溶液中添加carboxymethyl-?-cyclodextrin (CM-?-CD)，在pH 6.0的情況下，達到最佳的分離效果。藉由結合常數的計算可以了解中性烷基?環分子與CM-?-CD的錯合模式 (1：1或2：1化學計量內包錯合物)，並搭配光譜技術，以證實毛細管電泳法所計算之結合常數與傳統光譜法計算結果之一致性。中性烷基?環分子在?位置上取代的異構物，如1-ethylnaphthalene, 1,4-dimethylnaphthalene兩種中性?環異構物，會與兩個CM-?-CD錯合形成2：1化學計量之主-客內包錯合物。藉由溫度的改變可以得知CM-?-CD與中性烷基?環分子在不同溫度下的結合常數變化，以計算主-客錯合作用的熱力學參數。CM-?-CD與中性烷基?環分子在?位置上之?S為正值，驗證CM-?-CD與?環?位置上的中性烷基?環分子錯合機制，在任何溫度下都可自發性的產生，且低溫下有較佳的錯合作用。 Capillary electrophoresis (CE) has been established as a powerful technique for separating an unusually large variety of compounds. This versatility is due in part to the ease and speed with which the CE running buffer can be altered with a variety of reagents to influence the migration rates. And CDs were commonly used host molecules. The family of cyclodextrins (CDs) is one of the most intensively studied macromolecular systems. The formation of cyclodextrin-based guest-host complexes is a simple model for studying molecular recognition processes, and has been employed in many applications, such as pharmaceutical, cosmetic and food industries. The separation and migration behavior of seven positional and structural neutral alkylnaphthalene derivatives in cyclodextrin-mediated electrokinetic chromatography were systematically investigated. The effective separation conditions were to use 10 mM phosphate buffer with negatively charged carboxymethyl-?-cyclodextrin (CM-?-CD) at pH 6.0. The guest-host interactions with both 1:1 and 1:2 binding stoichiometries for various derivatives have been evaluated by comparing the apparent binding constants, the results reveal that the substituent group(s) attached to the naphthalene ring significantly affected the inclusion stoichiometric behaviors. Alkylnaphthalene derivatives with the substituent(s) at 1-position(s), such as 1-ethylnaphthalene, 1,4-dimethylnaphthalene, may undergo complexation with one and two CM-?-CD molecules. The binding constants of these derivatives agreed closely with the data obtained by a photometric method. The thermodynamic parameters were also calculated to improve our understanding of the interaction between the neutral alkylnaphthalene derivatives and CM-?-CD at various temperatures. The positive entropy (?S?) values for the alkylnaphthalenes with the substituent(s) at 2-position(s) indicate that the inclusion of the guest molecule into the cavity of CM-?-CD is favored at all temperatures.
顯示於類別:	[化學研究所] 博碩士論文

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