Track-etched functionalized nanoporous beta-PVDF membrane electrodes, or functionalized membrane electrodes (FMEs), are electrodes made from track-etched, poly(acrylic acid) (PAA) functionalized nanoporous beta-poly(vinylidene fluoride) (beta-PVDF) membranes with thin porous Au films sputtered on each side as electrodes. In order to form the P-PVDF nanoporous membranes, beta-PVDF films are irradiated by swift heavy ions. After irradiation, radical tracks are left in the membranes. Etching removes some of the radical tracks revealing nanopores. The remaining radicals initiate radio grafting of PAA from the pore walls of the nanoporous beta-PVDF. PAA is a cation exchange polymer that adsorbs metal ions, such as Pb(2+), from aqueous solutions thus concentrating the ions into the membrane. After a calibrated time, the FME is transferred to an electrochemical cell for analysis. A negative potential is applied to the Au film of the FME for a set time to reduce the adsorbed ions onto the Au film working electrode. Square-wave anodic stripping voltammetry was performed on the FME to determine the Pb(2+) ion concentration in the original solution based on calibration. The zero current intercept of the calibration for Pb(2+) is 0.13 ppb (mu g L(-1)) and three times the sample blank deviation (3S/N) is 0.050 ppb.