An electrochemical sensor based on PEI/CS/GN composite–modified glassy carbon electrode for determination of Pb(II)

A novel electrochemical sensor has been developed in response to sensitive Pb(II) determination with graphene (GN) by ultrasonic dispersed, chitosan (CS) and polyethylene-imine (PEI) composite coated onto the surface of glassy carbon electrode (GCE). The micromorphology, structure, and electrochemical properties of the PEI/CS/GN composite–modified electrode were studied by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV), chronocoulometry (CC), and the differential pulse anodic stripping voltammetry (DPASV). It was discovered that CS/GN electrode provided a significant platform for detection of Pb(II). With the introduction of PEI, the modified electrode demonstrated a good enhancement in voltammetric response because PEI contains large amino groups and has a good response characteristic to heavy metal ions. Moreover, the intensity of volt-ampere response was associated with the weight ratio of PEI, and it displayed a best status when its weight ratio to CS was 30wt%. Under the optimal conditions, there was a great linear correlation (R2 = 0.999) for PEI/CS/GN composite–modified GCE in the Pb(II) concentration range of 0.5 ~ 90 μg/L, and the limit of detection (LOD) was down to 0.01 μg/L based on the signal-to-noise ratio (S/N = 3). The prepared PEI/CS/GN electrode has the advantages of simple preparation, environmental protection, large specific surface area, and rapid electron transport, and which has huge potential application in Pb(II) determination.