Abstract: The effects of macromolecular compounds (polyvinyl alcohol (PVA), arabic gum)-Triton X-100 mixture on the coloured ion-associated complex systems are investigated. It is found that these mixtures have good solubilization actions on many coloured ion-association complexes. The mechanism of the effect may be the synergism of PVA(arabic gum) and TritonX-100 which changes the microenvironment of the colour system. It creates a steric environment that is both benificial to the formation of ion-association complex and the accumulation of more colour reagent molecules. The formation of the complicated ion-association complex carried non-stoichiometric additional reagent molecules results in an increase of sensitivity.

Key words: Mixed solubilizer, Coloured ion-association complex system, Non- ionic surfactant