Modification of electrode surface with covalently functionalized graphene oxide by l-tyrosine for determination of dopamine

Abstract An l -tyrosine ( l -Tyr) covalently functionalized graphene oxide (GO) composite (Tyr–GO) has been prepared through amide bonds, which is further used to modify glassy carbon electrode (GCE) by simple dipping-drying method. The differential pulse voltammetry (DPV) peaks of dopamine (DA) and ascorbic acid (AA) can be completely separated with a peak potential difference of 414 mV by using the fabricated Tyr–GO/GCE, holding promise for simultaneous determination of DA and AA. The peak currents are linearly with the concentration of DA in the range from 1.0 × 10 −6 to 5.0 × 10 −4  mol/L with a detection limit of 2.8 × 10 −7  mol/L. In addition, the modified electrode exhibits excellent reproducibility and stability.