Utilization of AuNPs dotted S-doped carbon nanoflakes as electrochemical sensing platform for simultaneous determination of Cu (II) and Hg (II)

Gold nanoparticles (AuNPs) dotted S-doped carbon (AuNPs/S-C) nanoflakes were synthesized via a facial and simple approach. Typical synthesis route involves the formation of gold nanoparticles/poly(3,4-ethylenedioxythiophene) (AuNPs/PEDOT) and a subsequent calcination process. Many techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) were used to characterize their morphology, structures and compositions . Results indicated that AuNPs with an average size of 5   nm were uniformly dotted on/into the S-C nanoflakes. The AuNPs/S-C/nafion was utilized as a new electrode material for simultaneously electrochemical determination of Cu (II) and Hg (II) using differential pulse anodic stripping voltammetry (DPASV) technique. Benefiting from the efficient metal-complexing ability and electrocatalytic activity of S-C and the good conductivity of AuNPs, the modified electrode exhibited enhanced electrochemical performance compared with bare glassy carbon electrode. Under optimal conditions, the peak currents displayed linear response to the concentrations of Cu (II) and Hg (II) ranges from 0.64 to 63.55   μg/L and 4.01 to 300.89   μg/L, with detection limits of 0.19   μg/L and 1.40   μg/L (S/N   =   3), respectively. The modified electrode was also applied for the determination of Cu (II) and Hg (II) in lake water samples with good results.