Quantitative Treatment of Ketal Hydrolysis in Aqueous Solutions Containing Polymer-Surfactant Complexes Using a Pseudophase Kinetic Model

Sodium dodecyl sulfate versus acid-labile surfactant gel electrophoresis: comparative proteomic studies on rat retina and mouse brain

A long-chain derivative of 1,3-dioxolane sodium propyloxy sulfate, with similar denaturing and electrophoretic properties as SDS, and facilitated protein identification following polyacrylamide gel electrophoresis (PAGE) for Coomassie-stained protein bands, has been tested. Comparative acid-labile surfactant/sodium dodecyl sulfate two-dimensional (ALS/SDS 2-D)-PAGE experiments of lower abundant proteins from the proteomes of regenerating rat retina and mouse brain show that peptide recovery for mass spectrometry (MS) mapping is significantly enhanced using ALS leading to more successful database searches. ALS may influence some procedures in proteomic analysis such as the determination of protein content and methods need to be adjusted to that effect. The promising results of the use of ALS in bioanalytics call for detailed physicochemical investigations of surfactant properties.

Ideal Mixing of Polymer-Surfactant Complexes of Polyethylene Oxide and Sodium Dodecyl Sulfate Plus Sodium Dodecanoate

Mixtures of the anionic surfactants sodium dodecyl sulfate (SDS) and sodium dodecanoate (SDoD) were investigated regarding their ability to bind to a hydrophilic nonionic polymer, polyethylene oxide (PEO). By electrical conductivity measurements, the parameters with respect to the onsets of surfactant aggregation were determined in the presence of 0.06 M PEO (critical aggregation concentration) and in its absence (critical micelle concentration). It was found that both plots of these parameters for the multicomponent mixtures against molar fraction of SDoD showed an ideal mixing behavior. The same technique was used to estimate the degree of ionization as a fundamental parameter relating to the interfacial composition of mixed aggregates. In addition, in order to monitor changes in polymer-surfactant structures, we used steady-state quenching fluorescence measurements to characterize the sizes of PEO-SDS/SDoD complexes at different compositions of the complex mixture. Copyright 1999 Academic Press.

The Absence of Conventional Polymer-Surfactant Interaction between Sodium Monodecyl Phosphate and Poly(ethylene Oxide): Conductivity and Kinetic Evidence

Mixtures of sodium monodecyl phosphate (NaDeP) and poly(ethylene oxide) (PEO) have been investigated conductimetrically in 0.05 M succinate buffer, pH 5.20. The conductivity vs NaDeP concentration profiles do not show the classical behavior of PEO-sodium dodecyl sulfate (SDS) mixtures. In the presence of different concentrations of PEO, the profiles exhibit only one discontinued point, whose SDS concentration values are similar to the NaDeP critical aggregation concentration. It was observed also that this conductivity breakpoint is not sensitive to variation in the polymer concentration and that it is independent of polymer molecular weight. However, the conductivity profiles of mixtures of NaDeP and SDS demonstrate behavior similar to that of SDS alone. For these mixtures, the evidence of binding, absent in the presence of NaDeP alone, is interpreted by assuming that it is solely driven by the SDS.