8-Quinolinol, formation constants with

The fast complexation rate of Zn(II) ion with 8-quinolinol (Hqn) or 5-octyloxymethyl-8-quinolinol (Hoeqn) at the 1-butanol/water interface was measured by the micro-two-phase sheath flow method [17], The formation of a fluorescence complex at the interface was measured within a period of less than 2 milliseconds after the contact of the two phases. The depth profile of the fluorescence intensity observed across the inner organic phase flow proved that the fluorescence complex was formed only at the interface and it increased in proportion to the contact time. The diflusion length of Hoeqn in the 1-butanol phase for 2 milliseconds was calculated as 0.8 pm, which is smaller than the experimental resolution depth of 2 pm in the microscopy used. Therefore, the observed rate constant was analysed by taking diffusion and reaction rates into account between Zn(II) and Hoeqn at the interfacial region by a digital simulation method. The digital simulation has been used in the analysis of electrode reactions,... 

Very promising is the application of micelles for differential reaction rate methods. Micelles can alter the rate constant ratio of two or more species that interact with a common reagent. Simultaneous kinetic determination of nickel and cobalt based on the complex formation with 5-octyloxymethyl-8-quinolinol in the nonionic micellar medium of Triton X-100 is effective as this surfactant decreases the rates of formation of both complexes compared with an aqueous medium, so permitting their spectropho-tometric monitoring. In the micellar medium the formation of the Co complex is 44 times faster than that of Ni, and determinations of both ions in the lO moll range are possible. 

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