DETERMINATION OF HYAMINE-2389 CRITICAL MICELLE CONCENTRATION (CMC) BY MEANS OF CONDUCTOMETRIC, SPECTROPHOTOMETRIC AND POLAROGRAPHIC METHODS

The critical micelle concentration (CMC) values of the Hyamine 2389 surfactant, an alkyl(C-9-C-15) benzyltrimethylammonium chloride, are determined. With the conductometric method the CMC value in distilled water is 0.67 g l-1. With the spectrophotometric method the CMC is 0.33 g l-1 when the Hyamine 2389-Xylenol Orange complex is used in the presence of 4.10(-3) M acetic acid/3.6.10(-3) M sodium acetate. With the polarographic method, involving measurement of the electrocapillary curves in the presence of 0.1 M potassium nitrate, two CMC values, 0.12 and 0.60 g l-1, are found due to the so-called sphere-to-rod transition.