Facile Fabrication of Zirconia Modified Screen-Printed Carbon Electrodes for Electrochemical Sensing of Phosphate

We report here a facile method to immobilize zirconia nanoparticles on a disposable screen-printed carbon electrode (designated as ZrO2-SPCE) for phosphate sensor application. Simply by ultrasonicating a bare SPCE in a ZrO2 slurry, ZrO2 nanoparticles can be immobilized effectively on the electrode surface as verified by surface characterization evidences. Using ferricyanide as a redox probe, an increase in the charge transfer resistance (R-ct) of ferricyanide upon adsorption of phosphate on ZrO2 is used for the determination of phosphate. This ZrO2-SPCE phosphate sensor shows a wide linear range up to 1mM and a detection limit of 1.69 mu M (S/N=3). Practical applicability of the ZrO2-SPCE is demonstrated by detecting phosphate content in human blood samples.