Studies on the effect of non-ionic surfactant micelles on color reactions: III. The effect of micelles on metal ion reactivity in the Fe(III)-PAN-Triton X-100 system

Fe(III) and PAN form Fe(PAN),OH complex in CHCl₃ extract which shows absorption maxima at 550 nm and 775 nm (log ε₅₅₀,= 4.06, log ε₇₇₅ = 4.08). In the Fc(III)-PAN-Triton X-100 system, two complex species Fe(PAN)₂⁺ and/or Fe(PAN)₂OH may be formed. Fe(PAN)₂⁺ possesses a strongly absorbing peak at 550 nm (log ε₅₅₀ = 4.36). In this paper the effect of Triton X-100 micelles on the Fe(III)-PAN color reaction has been investigated in detail. We consider that the high density of ether linkages in Triton X-100 micelles concentrate hydrous Fe(III) ions and change their existing state. Moreover, the micelles not only raise the reactivity of Fe(III), but also enhance the rate of the color reaction.