A cellulose acetate membrane, positioned in a passive sampler system, was coated with the perfluorinated polymer Nafion. Aqueous metal transport through the membrane and the Nafion film was investigated. The Nafion-coated membrane prevents the transport of metals bound to natural organic material to the receiving phase in the passive sampler, while copper associated with small synthetic ligands pass through the Nafion film. Increasing thickness of the Nafion film decreases the metal uptake rate to the receiving phase in the passive sampler and increases the response time. A decreased response time for the passive sampler would provide a better estimation of rapid changes in concentration, particularly for dynamic aquatic systems such as urban runoff. Limited biofouling protection with the Nafion coating was demonstrated by growth inhibition of natural periphyton communities on glass surfaces.