Electrochemical detection of heavy metals and chloramphenicol at nafion/graphene quantum dot modified electrode

Abstract

Graphene quantum dots (GQDS) with uniform particle size were successfully prepared by a simple in-situ electrolytic graphite rod method at a certain current density, and nafion/GQDS modified glassy carbon electrodes (nafion/GQDS/GCE) were constructed. Anodic stripping voltammetry and differential pulse voltammetry were applied to heavy metal Pb(Ⅱ) respectively. Electrochemical detection of CD(Ⅱ) and chloramphenicol. The results showed that the dissolution current of Pb (Ⅱ) and CD(Ⅱ) increased with the increase of their concentration, and showed a good linear relationship. The linear range of Pb (Ⅱ) was 4.82×10^-8~9.65×10^-7mol/L (R²=0.9923), CD (Ⅱ) linear range is 1.07×10^-7~1.96×10^-6mol/L (R²=0.9912), the detection limits of Pb (Ⅱ) and CD (Ⅱ) are 1.61×10^-8mol/L and 3.57×10^-8mol/L respectively. The nafion/GQDs/GCE has obvious electrocatalytic reduction effect on chloramphenicol. The electrocatalytic mechanism is an irreversible reaction involving 6 Electrons, and the electron transfer rate constant KS is 105.4s^-1. The catalytic reduction current of chloramphenicol at the modified electrode is 5.00×10^-7~2.50×There is a good linear relationship in the range of 10^-3mol/L, and the detection limit (S/N=3) is 1.67×10^-7mol/L. The nafion/GQDs/GCE also has good anti-interference performance. Stability and reproducibility, and satisfactory results were obtained for the detection of actual samples.