A thin poly(acridine orange) film containing reduced graphene oxide for voltammetric simultaneous sensing of ascorbic acid and uric acid

We have fabricated, in a single step, carbon ceramic electrodes modified with a poly(acridine orange) film containing reduced graphene oxide. They display electrocatalytic activity to ascorbic acid (AA) and uric acid (UA) at pH 4.5. The anodic peak potentials of AA and UA are separated by 276 mV so that they can be well resolved in cyclic voltammetry. UA and AA were simultaneously determined in a mixture at working potentials of 170 and 400 mV, respectively. Under optimized conditions, the calibration curves for AA and UA cover the 0.8–5,000 μM and 0.6–900 μM concentration range, respectively, while detection limits are 0.3 μM and 0.2 μM. The electrode was applied to determine AA and UA in urine samples. DPV curves of RGO–PAO/CCE in the phosphate buffer solution (pH 4.5) containing 5.0 × 10 −5  mol L −1 AA with different concentration of UA (a → f: 0, 1, 3, 5, 7, 9 × 10 −6  mol L −1 )