Performing enzyme-free H2O2 biosensor and simultaneous determination for AA, DA, and UA by MWCNT–PEDOT film

An enzyme-free hydrogen peroxide (H2O2) biosensor based on MWCNT–PEDOT film modified electrode has been successfully performed on glassy carbon electrode (GCE) and indium tin oxide (ITO) electrode. At an applied potential of −0.5 V vs. Ag/AgCl, the MWCNT–PEDOT electrode exhibited linearly dependence on H2O2 concentration in the range of 0.1–9.8 mM. It can be observed two significantly linear sections. One shows sensitivity of 943 μM mM−1 cm−2 with signal/noise of 6; and the other one shows sensitivity of 174 μM mM−1 cm−2 with signal/noise of 4 in pH 7 PBS. It also presented excellent stability at room temperature, with a variation of response current less than 5% over 30 days. Moreover, the sensor was characterized by cyclic voltammetry (CV), scanning electronic microscopy (SEM), atomic force microscopy (AFM), and different pulse voltammetry (DPV). This sensor also can simultaneously detect AA, DA, and UA and can be utilized to develop multifunctional biosensors.