Transfer reactions of alkali metal ions, either direct or facilitated by the ionophores dibenzo-18-crown-6 and valinomycin, have been studied at the water\2-nitrophenyloctylether-polyvinyl chloride gel micro-interface. The polarised micro-hole array interface between water and the composite polymer membrane is used as a selective transducer for the amperometric detection of alkali metal ions. The formal Gibbs transfer energies of ion transfer from the aqueous phase to the 2-nitrophenyloctylether-polyvinyl chloride gel phase are evaluated from voltammetric measurements. The association constants are calculated to determine the selectivity imparted by the ionophores such as dibenzo-18-crown-6 and valinomycin on transferring the alkali metal ion at the gel micro-interface.