Electrochemical behavior of Pb (II) on a heparin modified chitosan/graphene nanocomposite film coated glassy carbon electrode and its sensitive detection.

In this study, we developed a novel composite material containing biological macromolecules like heparin and chitosan coated on reduced graphene oxide (rGO) for the modification of glassy carbon electrode (hep/CS-rGO/GC). It can be applied for the sensitive electrochemical detection of Pb ²⁺ by square wave anodic stripping voltammetry (SWASV). The physicochemical analysis such as XRD, FTIR, FESEM and Raman spectroscopy techniques revealed that an effective functionalization occurred at the rGO surface. The consequence of deposition and stripping of metal ions by various electrochemical parameters such as supporting electrolytes, pH value, deposition potential, and deposition time were carefully studied and optimized. Under the optimized conditions, the linear calibration curve was calculated to be from 1.125 to 8.25μgL ^-1 for Pb ²⁺ with the correlation coefficient (R ² ) 0.9988. The detection limit and sensitivity achieved for the modified electrode were 0.03μgL ^-1 and 1.34μA/nM respectively. Furthermore, the electrochemical investigation indicates that the hep/CS-rGO composite electrode exhibits high selectivity, strong adherence to the electrode surface, good stability and reproducibility towards the detection of Pb ²⁺ . Finally, hep/CS-rGO/GC electrode was assessed by the quantity of Pb ²⁺ present in the practical samples, and the determined results were consistent with that of AAS.
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