Freitag D, Schmitt-Kopplin P, Simon R, Kaune A, Kettrup A
GSF-National Research Center for Environment and Health, Institute of Ecological Chemistry, Neuherberg, Germany.
Electrophoresis. 1999 Jun;20(7):1568-77. doi: 10.1002/(SICI)1522-2683(19990601)20:7<1568::AID-ELPS1568>3.0.CO;2-W.
The electrophoretic behavior of fourteen 4,6-diamino-s-triazines was investigated in the presence of an anionic surfactant (sodium dodecyl sulfate, SDS) using micellar capillary electrophoresis (MCE). The measurements were performed at the pH of zero charge of the hydroxytriazines and the existence of strong ionic and H-bond interactions of hydroxy-s-triazine species with the anionic micelles could be shown. Their migration behavior was compared to the n-octanol-water partition coefficients (log Kow) measured with reverse-phase HPLC and calculated with different fragment contribution methods. A partition model was proposed to understand the interactions of the three major hydroxy-s-triazine species: cationic, anionic and neutral (presenting enol and keto forms) with the charged SDS micelles taken as model for charged natural polyelectrolytes like humic substances. These results strongly indicate that hydroxy-striazines are polarized in the presence of the charged micelles and that they are essentially present in their keto form in the micellar phase (and enol form in the water phase), confirming previous studies suggesting the presence of zwitterionic resonance structures at a neutral pH around their isoelectric point.
使用胶束毛细管电泳（MCE）在阴离子表面活性剂（十二烷基硫酸钠，SDS）存在的情况下研究了十四种4,6 - 二氨基 - s - 三嗪的电泳行为。测量是在羟基三嗪的零电荷pH值下进行的，并且可以证明羟基 - s - 三嗪物种与阴离子胶束之间存在强离子和氢键相互作用。将它们的迁移行为与用反相高效液相色谱法测量并用不同片段贡献方法计算的正辛醇 - 水分配系数（log Kow）进行比较。提出了一个分配模型来理解三种主要的羟基 - s - 三嗪物种：阳离子、阴离子和中性（呈现烯醇和酮形式）与带电的SDS胶束之间的相互作用，带电的SDS胶束被用作腐殖质等带电天然聚电解质的模型。这些结果有力地表明，羟基 - 三嗪在带电胶束存在下会极化，并且它们在胶束相中基本上以酮形式存在（在水相中以烯醇形式存在），这证实了先前的研究表明在其等电点附近的中性pH值下存在两性离子共振结构。
