Ultra-sensitive voltammetric simultaneous determination of dopamine, uric acid and ascorbic acid based on a graphene-coated alumina electrode

The authors describe the fabrication of an interconnected edge-exposed graphene nanostructure via chemical vapor deposition (CVD) of foliated graphene onto a network of alumina nanofibers. The fibers such obtained are shown to enable ultra-sensitive voltammetric determination of dopamine (DA), uric acid (UA) and ascorbic acid (AA). The electrode displays powerful and persistent electro oxidative behavior and excellent electron transport properties. Cyclic voltammetry and differential pulse voltammetry demonstrate excellent selectively and sensitivity for AA, DA and UA, with typical peaks at −0.08 V, +0.19 V, and +0.34 V (vs. SCE), respectively. Under optimum conditions, the calibration plots are linear in the 1–80 μM range for DA, in the 1–60 μM range for UA, and in the 0.5–60 μM range for UA, with detection limits of 0.47 μM, 0.28 μM and 0.59 μM, respectively. The sensor was successfully applied to the simultaneous determination of DA and UA in the presence of AA in spiked urine sample.