Highly Selective Electrochemical Sensing of Dopamine, Xanthine, Ascorbic Acid and Uric Acid Using a Carbon Fiber Paper

Biological compounds like Dopamine (D), Xanthine (X), Ascorbic acid (AA) and Uric acid (UA) play a vital role in food, clinical and human metabolism. Since these compounds are present in biological fluids and have close standard potentials-values, it is imperative to choose a method to sense these fluids without any electrochemical interference. Toray paper, with a porous gas diffusion layer imbibed with denser carbon fibers, is an excellent option that can be utilized as a working electrode for such sensing applications. Herein, the electroactivity of these compounds was tested using cyclic voltammetry and square wave voltammetry without any interference. The linear ranges for the compounds (D, X, AA, UA) are 10-1000 μM, 7-300 μM, 100-1000 μM and 301000 μM respectively, while the limits of detection are 9.67 μM, 6.54 μM, 97.12 μM and 28.74 μM respectively with S/N ratio of 1.5. Finally, the electrode was tested with human serum samples for the identification of D, X, AA and UA manifesting exceptional reproducibility.