VARIATION OF THE CRITICAL MICELLE CONCENTRATION OF SODIUM DODECYL-SULFATE WITH IONIC-STRENGTH MONITORED BY SELECTIVE-ION MEMBRANE ELECTRODES

The operation of a selective-ion membrane electrode (sensitive to the dodecyl sulphate ion) is described. The reported minimum in the graph of emf developed against concentration was investigated to assess whether this could be ascribed to the critical micelle concentration of the surfactant species. This was attempted by monitoring the position of the observed minimum as a function of the ionic strength. It was found that the movement produced was entirely analogous to that observed by other procedures, confirming that the minimum is a result of some change occurring at the CMC. © 1979 Dr. Dietrich Steinkopff Verlag.