STOICHIOMETRIC AND KINETIC STUDY OF ION ASSOCIATION INVOLVING SOLVATOCHROMISM AND ITS USE IN ANALYTICAL CHEMISTRY

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The present investigator found that some dye ions reacted with their pairing ions in an aqueous solution to form ion associates and to change the maximum absorption wavelengths and its absorption intensity. The change in absorption wavelength and intensity was found to be caused by "solvatochromism". Such solvatochromism has been studied in detail by using newly designed and synthesized dye ions. The solvatochromism, which was found a new-type phenomenon, was occurred on the basis of the change in the polarity of the micro-environment around the dye ions, when they reacted with hydrophobic pairing ions to form ion associates. By utilizing the color change reactions, the ion association reactions in aqueous solutions were studied stoichiometrically and kenetically. Ion association constants of various hydrophobic ion associates formed in aqueous solutions were first determined spectrophotometrically, as well as by a mobility change method using capillary elelctrophoresis and by a photom … More etric titration method. The ion association reactions with newly developed reagents were applied to the analysis of various ionic substances such as cationic, anionic and nonionic surfactants and phosphate and silicate coupled with the formation of heteropoly acids. The results obtained in this research are summarized as follows.1. Sysnthesis and developments of novel ion association reagents. Two types of reagents, which showed the shift of maximum absorption wavelength toward a shorter and a longer wavelengths in the presence of pairing ions, were developed.2. Determination of ion association constants in aqueous solutions. The constants of hydrophobic ion associates were determined by using the solvatochromism and the change in ionic mobility, and by analysing the photmetric titration curves. Thermodynamic study of ion association was carried out, which showed the entropy change involging ion association was very important.3. Analytical uses. The newly developed in association reagents were used for the spectrophotometric determination of ionic substances for flow injection analysis, for the detection in post column coloration, for photometric titration and for the separation and detection in capillary electrophoresis. Less