A novel potentiometric hydrogen peroxide sensor based on pK_a changes of vinylphenylboronic acid membranes

摘要

A potentiometric hydrogen peroxide (H_2O_2) sensing scheme was developed using arylboronic acid as the electrode modifier. It is well-known that both aliphatic and aryl boronic acid undergo electrophilic displacement reaction with H_2O_2. This reaction involves replacement of boronic acid by the hydroxyl group of peroxide resulting in a change in pK_a value that can be exploited for sensing of H_2O_2. Vinylphenylboronic acid (VPBA) ink was prepared using Nation as the binder and it was drop cast on an electrode surface. Morphology of the modified electrode was analysed using scanning electron microscopy (SEM). The present modifier exhibited a linear relationship between the difference in electrode potential (AEp) vs. [H_2O_2] with a Nernstian slope of 26 ±2 mV in the concentration range of 10~(-1)-10~(-5)M. Application of the VPBA modified electrode for hydrogen peroxide sensing was studied in an industrial dye-bleach effluent.