Noise Analysis of Ion Transfer Kinetics at the Micro Liquid/Liquid Interface

Fluctuation analysis was utilized to determine the TEA ion transfer kinetics across the water/1,2-dichloroethane interface. The average value k(s) = 0.34 cm s(-1) is comparable with the previously reported value k(s) = 0.2 cm s(-1), derived from electrochemical impedance spectroscopy experiments. The experimental approach utilizing a thick wall glass micro-capillary to fix the interface exhibits a very small stray capacitance value, proving this system to be suitable for determining the kinetics of the fast ion transfer across a liquid/liquid interface. Application of a method employing a small perturbation signal prevents polarization of the inner capillary surface by current flowing through the cell. The induced polarization of the capillary can affect ion concentration at the interface due to electroosmosis and thus make the kinetics data evaluation difficult or erroneous.