Amperometric sensor for dopamine based on surface-graphenization pencil graphite electrode prepared by in-situ electrochemical delamination

A surface-graphenized pencil graphite electrode (SGPGE) served as an amperometric sensor for dopamine (DA). It was prepared through a one-step in-situ electrochemical graphene delamination. The graphite particles on the outer surface of the pencil graphite electrode (PGE) were delaminated by controlling the electrochemical delaminating conditions such as the applied anodic voltage and polarization duration, as well as the kind ofelectrolytes. The best conditions were identified by scanning electron microscopy, Raman spectra, cyclic voltammetry and differential pulse voltammetry (DPV). As a result, the electrode was endowed with an optimum combination of graphene delamination efficiency and electrochemical activity. The electrochemical treatment activates the surface sensing sitesandimproves the sensing performance. The NaOH-teated anodically graphenized electrode was used to sense dopamine by DPV. The bestoxidation voltage of dopamine is ataround 0.17V (vs. SCE). The electrode respondsy to dopamine in the ranges of 0.15 to 45M, the detection limit is 8.2nM (S/N=3), andthe sensitivity is 20.81AM(-1)cm(-2). In real human urine samples, the sensor exhibited detection recoveries of 97.4-98.8% and low relative standard deviations of 3.49-3.92%.