摘要
以酚酞作为光谱探针 ,采用紫外 -可见光谱法研究了在pH =10 .5的缓冲液中 β -环糊精与DHA包结物的制备 ,结果表明 ,1分子DHA与 3分子 β -环糊精依据范德华作用力和疏水作用力发生包结作用 ,生成稳定的包结物。包结物适宜的制备条件为 :β -环糊精与DHA的摩尔比为 3∶1,主客体溶液的浓度比为12 .5∶1;包结温度 2 8℃ ;反应时间 2 .2h。多种弱相互作用力协同作用于 β -环糊精的配位包结过程 ,主 -客体间的尺寸匹配决定所形成包结物的稳定性 ,根据竞争包结理论 ,用Hidebran -Benesi方程测定了 2 5℃条件下的包结物稳定常数为 9.2 6× 10 13L/mol,包结物稳定。包结物中DHA的氧化稳定性得到显著改善。
Spectrophotometric titration were performed in aqueous buffer solution(pH=10.5) to determine the binding constants of β-cyclodextrin(β-CD) with docosahexenoic acid (DHA), a kind of guest molecules, using phenolphthalein as a spectral probe. The results indicate that 3 moles of β-CD can include one mole DHA to form inclusion compound by means of several weak interaction and force, -Van Der Waals force and hydrophobic interaction, et al. The optimum reaction conditions for inclusion compound of β-CD with DHA: the mole ratio of β-CD/DHA is 3∶1(mol/mol) and concentration ratio of β-CD/DHA is 12.5∶1(mol·L-1/mol·L-1) in the H 2O + ethanol solution, the time and temperature of included reaction are 2.2h and 28℃. Complex stability is dominated by the size/sharp-matching between host and guest. Equilibrium constant of inclusion compound (Ks) of β-CD with DHA is 9.26×10 13L/mol. The resistance to oxidation is increased by inclusion with β-CD.
出处
《中国粮油学报》
EI
CAS
CSCD
北大核心
2004年第4期84-88,共5页
Journal of the Chinese Cereals and Oils Association
