It bases on the fact that in acetic acid medium, Hg2+ ion can catalyze the substitute reaction of CN ligand in [Fe(CN)6]4-by 2,2'-bipyridyl (bipy), and the resultant [Fe(bipy)3]2+ cation can react with FinBr4 anion of tetrabromofluorescein (HFinBr4) to form ion association complex [Fe(bipy)3]2+[(FinBr4)2]2- which can emit phosphorescent signal on filter paper substrate.

The RRS intensity was enhanced greatly when Co(Ⅱ) reacted with PAN to form cation chelate complex which further reacted with SDBS to form an ion-association complex in a pH=9.

4,Raloxifene reacts with Evans blue and forms an ion-association complex.

This paper introduced the application of ion-association complex for the Solid-Phase Reflection Spectrophotometry which is used in Silver analysis.

Study on flotation separation of cadmium(Ⅱ) by ionic associated system;

A highly sensitive spectrophotometric method was developed for the determination of trace amounts of Iodine based on the oxidation of I~- to I_3~- by IO_3~- and the further reaction of I_3~- with acridine red to form the ion-association complex [AO][I_3]in dilute phosphoric acid solution.

8 KHC_(8)H_(4)O_(4)-HCl buffer solution, in the presence of gum arabic and polyvinyl alcohol ,IO~-_3 oxidated I~- to produce I~-_3, then I~-_3 reacted with methylene blue to form an ion-association.

The formation of an ion-association among As-Sb-Mo blue and rhodamine B is well distributed in aqueous solution as a steady system under the existence of polyvinyl alcohol .