Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, CEP 05508-900, SP, Brazil; Department of Pharmaceutical Technology, Institute of Pharmacy, Friedrisch Schiller Universität - Jena, 07743 Jena, Germany.
J Colloid Interface Sci. 2012 Apr 1;371(1):62-72. doi: 10.1016/j.jcis.2011.12.072. Epub 2012 Jan 21.
Interfacial concentrations of chloride and bromide ions, with Li(+), Na(+), K(+), Rb(+), Cs(+), trimethylammonium (TMA(+)), Ca(2+), and Mg(2+) as counterions, were determined by chemical trapping in micelles formed by two zwitterionic surfactants, namely N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (HPS) and hexadecylphosphorylcholine (HDPC) micelles. Appropriate standard curves for the chemical trapping method were obtained by measuring the product yields of chloride and bromide salts with 2,4,6-trimethyl-benzenediazonium (BF(4)) in the presence of low molecular analogs (N,N,N-trimethyl-propane sulfonate and methyl-phosphorylcholine) of the employed surfactants. The experimentally determined values for the local Br(-) (Cl(-)) concentrations were modeled by fully integrated non-linear Poisson Boltzmann equations. The best fits to all experimental data were obtained by considering that ions at the interface are not fixed at an adsorption site but are free to move in the interfacial plane. In addition, the calculation of ion distribution allowed the estimation of the degree of ion coverage by using standard chemical potential differences accounting for ion specificity.
界面处的氯离子和溴离子浓度，以及作为反离子的锂离子、钠离子、钾离子、铷离子、铯离子、三甲铵离子、钙离子和镁离子，通过两种两性离子表面活性剂（即十六烷基-N,N-二甲基-3-氨丙基磺酸盐（HPS）和十六烷基磷酸胆碱（HDPC）胶束）形成的胶束中的化学捕获来测定。通过测量存在低分子类似物（N,N,N-三甲基丙烷磺酸盐和甲基膦酰胆碱）时 2,4,6-三甲基苯重氮盐（BF(4)）与氯化物和溴化物盐的产物产率，获得了化学捕获方法的适当标准曲线。通过完全集成的非线性泊松-玻尔兹曼方程对实验测定的局部 Br(-)（Cl(-)）浓度值进行建模。通过考虑到界面处的离子不是固定在吸附位点上，而是可以在界面平面内自由移动，对所有实验数据进行了最佳拟合。此外，离子分布的计算允许通过使用考虑离子特异性的标准化学势差异来估计离子覆盖度的程度。
