Electrodes modified with sulphonated poly(aryl ether sulphone) : effect of casting conditions on their enhanced electroanalytycal performance

Linear sulphonated poly(arylethersulphone) (SPAES) membranes were tested and compared
with Nafion, as electrode modifiers for electroanalytical purposes. Different preparation
parameters were evaluated: casting solvent, method of drying and storage, polymer ionic
moieties counter-ion. In particular, the casting solvent seems to play a key role in the final
modified electrode performances. Four solvents characterized by different boiling point and
polarity were tested: dimethylformamide (DMF), N,N-dimethylacetamide (DMAc),
dimethylsulfoxide (DMSO), N-methylpyrrolidone (NMP). The best electrode, particularly in
terms of highest peak currents, was the one prepared using a 1% m/v solution of polymer in
NMP, dried at 25 °C in a drying oven. Its performances are explained in terms of a
favourable membrane organization enabling a thin layer diffusion and/or a preconcentration
mechanism.