Polypyrrole Hollow Nanotubes Loaded with Au and Fe3O4 Nanoparticles for Simultaneous Determination of Ascorbic Acid, Dopamine, and Uric Acid

An ultrasensitive electrochemical biosensor was fabricated for electroanalytical determination of ascorbic acid(AA), dopamine(DA) and uric acid(UA) individually and simultaneously based on polypyrrole hollow nanotubes loaded with Au and Fe3O4 nanoparticles(NPs) uniformly(PPy@Au-Fe3O4). The PPy@Au-Fe3O4 nanotubes were synthesized in one-pot using MoO3 nanorods as templates and the polymerization of Py, the formation of Au and Fe3O4 NPs and the removel of MoO3 templates took place stimultaneously. Electrochemical studies reveal that PPy@Au-Fe3O4 modified glassy carbon electrode(GCE) possesses excellent electrocatalytic activities toward the oxidation of AA, DA and UA. Their oxidation peak currents increase linearly in the concentration ranges of 1-2000 mu mol/L for AA, 0.01-25 and 25-300 mu mol/L for DA and 0.1-300 mu mol/L for UA. Their detection limit values(S/N=3) were calculated as 0.45, 0.0049, and 0.051 mu mol/L for AA, DA and UA in the individual detection. By changing the concentrations simultaneously, the calibration curves showed linearity to 1000, 200, and 200 mu mol/L with detection limit of 0.39, 0.0060, and 0.060 mu mol/L for AA, DA, and UA, respectively. Finally, the obtained biosensor was successfully applied to the detection of AA, DA, and UA with satisfactory results on actual samples.

Automated summary

An ultrasensitive electrochemical biosensor with excellent electrocatalytic activities was fabricated for the detection of ascorbic acid, dopamine, and uric acid individually and simultaneously. The biosensor, based on polypyrrole hollow nanotubes loaded with gold and iron oxide nanoparticles, showed linear responses and low detection limits for the analytes in both individual and simultaneous detections. The biosensor was successfully applied to the detection of the analytes in actual samples.