Voltammetric uric acid sensor based on a glassy carbon electrode modified with a nanocomposite consisting of polytetraphenylporphyrin, polypyrrole, and graphene oxide

The article describes an electrochemical sensor for the detection of uric acid (UA) by using a glassy carbon electrode (GCE) modified with a composite consisting of polytetraphenylporphyrin, polypyrrole, and graphene oxide. The PPy/GO nanocomposites were synthesized by in-situ chemical oxidation polymerization. Microspheres loaded with p-TPP were mixed into the PPy/GO nanocomposite, deposited on the GCE and dried upon which aggregation occurs. The nanocomposites were characterized by scanning electron microscopy, FTIR and Raman spectroscopy. The sensor was applied to the voltammetric determination of UA by differential pulse voltammetry (DPV). The oxidation current varies with the UA concentration in the range from 5 to 200 μM, and electrochemical response is distinctly improved compared to GCEs modified with p-TPP or PPy/GO only. The modified electrode shows excellent linearity, lower detection limit of 1.15 μM. The results also demonstrate that the modified electrode exhibited good selectivity and sensitivity toward UA even in the presence of AA and DA. (author)