Simultaneous detection of ascorbic acid and uric acid using a fluorosurfactant-modified platinum electrode

We describe the oxidation of ascorbic acid (AA) and uric acid (UA) at a fluorosurfactant (Zonyl FSO) modified platinum electrode (FSO–Pt). The adsorption of FSO molecules on the electrode surface rendered the oxidation of both species more facile and their voltammetric peaks well separated. On the contrary, the growth of Pt surface oxides and the anodic responses of a variety of interfering electroactive biomolecules (such as cystine, oxalate, purine, glucose, etc.) were greatly suppressed. The unique features of the FSO–Pt electrode allow for the development of a highly selective and sensitive method for simultaneously detecting AA and UA. Since the modification of Pt electrodes was only based on the physical adsorption of the fluorosurfactant species, the preparation and renewal of the electrodes were very simple and easy to automatize, which may offer distinct advantages as compared with other electrode modification strategies. The practical application of the method has been demonstrated by the measurements of AA and UA in a human urine sample.