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

• l-Tyr covalently functionalized GO composite was prepared through amide bonds.
• The synergistic effect of Tyr and GO increased electrochemical activity of GCE.
• Tyr–GO/GCE exhibited good sensitivity, selectivity and stability for DA detection.

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.