Characterization and thermodynamic studies of the interactions of two chiral polymeric surfactants with model substances: phenylthiohydantoin amino acids.
Characterization and thermodynamic studies of the interactions of two chiral polymeric surfactants with model substances: phenylthiohydantoin amino acids.
复制标题
两种手性聚合物表面活性剂与模型物质苯硫内酰脲氨基酸相互作用的表征和热力学研究。
DOI：
10.1021/ac990212i
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发表时间：
1999
影响因子：
7.4
通讯作者：
Warner,IM
中科院分区：
文献类型：
--
作者：
Yarabe,HH;Shamsi,SA;Warner,IM
分析超速离心用于测定不同温度下聚十一酰基-L-缬氨酸钠（PSUV）和聚（十一酰基-L-苏氨酸钠）（PSUT）的分子量和沉降系数。吸光度与半径的关系图表明 PSUV 和 PSUT 都具有高度单分散性。提出了一种使用密度测量来评估部分比容的方法。 PSUV的部分比容略高于PSUT。此外，动电色谱中保留因子的温度依赖性用于估计表面活性剂/分析物复合物的焓、熵和吉布斯自由能。分离出五种苯硫基乙内酰脲-dl-氨基酸，并且每个对映体对都被完全解析。使用范特霍夫关系对 PSUV 与 PSUT 获得的热力学值进行比较表明，PSUT 具有不太有利的自由能变化（即较小的负 Δ(ΔG)），但会产生更大的正熵变化，因此手性分辨率稍低。
Analytical ultracentrifugation is used for determination of the molecular weights and the sedimentation coefficients of poly(sodium undecanoyl-l-valinate) (PSUV) and poly(sodium undecanoyl-l-threoninate) (PSUT) at different temperatures. Plots of absorbance as a function of radius indicates that both PSUV and PSUT are highly monodispersed. A method for evaluating the partial specific volumes using density measurements is presented. The partial specific volumes of PSUV are slightly higher than those of PSUT. In addition, the temperature dependence of the retention factor in electrokinetic chromatography was used to estimate the enthalpy, the entropy, and the Gibbs free energy of the surfactant/analyte complexes. Five phenylthiohydantoin-dl-amino acids were separated and each enantiomeric pair was completely resolved. Comparison of the thermodynamic values obtained with PSUV vs PSUT using a van't Hoff relationship suggests that PSUT, with a less favorable free energy change (i.e., less negative Δ(ΔG)), generates a more positive entropy change, hence slightly less chiral resolution.