Novel solvent systems for the preparation of phase-inversion cellulose acetate size exclusion membranes: Voltammetric investigations

Novel solvent systems have been developed for the casting of size exclusion electrode modifications by the phase‐inversion process. Solvent systems studied were (solvent/nonsolvent): pyridine/2‐octanol, pyridine/cyclohexanol, acetone/2‐octanol, tetrahydrofuran/aqueous Mg(ClO4)2, and tetrahydrofuran/toluene. These were compared to modifications made from the solvent system acetone/aqueous Mg(ClO4)2. The membranes were cast onto Pt microelectrodes embedded in glass. Cyclic voltammograms were recorded once per min after immersing the membrane‐modified electrode into a solution containing an electroactive species. Modified electrode response time to a concentration perturbation is correlated with the percent nonsolvent and percent polymer in the casting solution. The magnitude of the current from a solution of a 1500 dalton polyethylene glycol ferrocene carboxylate ester solute, and good casting reproducibility. This formulation is recommended for permselective coating applications; applications to biosensors are envisioned.