Detection of bioactive surfactants in aqueous solutions on the basis of H2O2-voltammetry

The voltammetric determination of surfactants at the hanging mercury drop e lectrode in aqueous solutions is described, based on the shift of the peak potential Delta E-P or the increase of the peak height Delta i(P) of the el ectroreduction of hydrogen peroxide or of the second oxygen reduction step, with increasing concentration of surfactants. Although the selectivity of this method is rather limited, it could be utilized, e.g., for monitoring t he absence (or presence) or for the determination of the contents of specif ied surfactants by comparing the obtained Delta i(P) (Delta E-P) signal wit h the reference state of the system or with that of a selected reference su rface active substance. As model surfactants n-octanol, tetrabutylammonium chloride and sodium dodecylbenzenesulfonate were used, the regular adsorpti on behavior of which is well known. The method was successfully applied to control the presence of a commercial detergent in water for rinsing bottles for infusion solutions.