Determination of Halide Concentrations at the Interface of Zwitterionic Micelles by Chemical Trapping: Influence of the Orientation of the Dipole and the Nature of the Cation

pH at the micellar interface: Synthesis of pH probes derived from salicylic acid, acid–base dissociation in sodium dodecyl sulfate micelles, and Poisson–Boltzmann simulation

“…2-7 and on pK a2 in Figs. [8][9][10][11]. Addition of SDS sharply increases pK a1 and pK a2 to a maximum value.…”

Micellar rate effects-assumptions and approximations

“…33 This electrostatic interaction, without ion specificity, was treated theoretically with simplifying approximations, 34a and later with inclusion of terms for specific ion binding, 34b but the model of preferred anion binding to sulfobetaine micelles and cation binding to phosphocholine micelles is inadequate, as shown by diazo trapping. 35 Ion-binding to zwitterionic micelles is specific for both co-and counter-ions, although it is much weaker than with ionic micelles. It is monitored by a variety of physical methods, including ionic conductance, the use of ion-specific electrodes, electrophoresis, and NMR spectroscopy and examples are given in the cited references.…”

“…It is monitored by a variety of physical methods, including ionic conductance, the use of ion-specific electrodes, electrophoresis, and NMR spectroscopy and examples are given in the cited references. Results from these physical methods can be related to those from diazo trapping 35 and kinetic studies of reactions with known mechanisms. The physical methods have limitations 36 in that only dilute electrolytes can be studied with ion specific electrodes and electrophoresis, while NMR spectroscopy is limited to some nuclei and diazo trapping cannot be used with very dilute solutions and some ions.…”

“…Diazo trapping with halide salts and both sulfobetaine and phosphocholine micelles, showed that halide ion uptake is higher with dicationic than monocationic salts, 35 indicating that both anions and cations are micellar bound . The simple rules applied earlier to micelle-ion interactions do not apply to zwitterionic micelles, except that ion-orders follow the Hofmeister series.…”

Miltefosine and BODIPY-labeled alkylphosphocholine with leishmanicidal activity: Aggregation properties and interaction with model membranes

“…Thus, electrostatic effects on the micelle-forming process may be in the source of the discrepant previous CMC values noted above. In fact, important electrostatic effects have been found in the study of the concentration of halide ions at the interface of zwitterionic micelles of zwitterionic amphiphilic 3-(N-hexadecyl-N, N-dimethylammonio) propane sulfonate (HPS) and miltefosine itself (50). In our experiments, despite the larger fluctuations observed in the values measured in the presence of NaCl, the values of the CMC of miltefosine remained around 50 μM and decreased in the order Milli-Q N buffer N buffer with NaCl (Table 1).…”