A novel carbon paste electrode for sensitive, selective and rapid electrochemical determination of chloride ion based on three-dimensional graphene

[Display omitted] •Carbon paste electrode was clarified for Cl− determination based on trace silver in graphite.•With the introduction of three dimensional graphene, the sensitivity was magnified 1500-fold.•After 100 test using a same electrode, the peak current of Cl− was still 90–110% of the first time.•Due to the outstanding performance, the proposed 3D-GN/CPE sensor has great potential in Cl− determination. A novel carbon paste electrode (CPE) modified with three-dimensional graphene (3D-GN) has been developed for sensitive, selective and rapid determination of chloride ion (Cl−) for the first time. Compared with bare carbon paste electrode (CPE) and graphene nanosheets modified CPE (GN/CPE), the peak current of Cl− on 3D-GN/CPE was sharply increased. The sensitivity achieved 0.156 μA mM−1 cm−2, which was nearly 1500-fold than bare CPE. The response time was less than 30 s and steady till 120 s. Using differential pulse voltammetry (DPV), the peak current at around 0.05 V was linear with the concentration of Cl− from 0.5 to 1000 mM, and the limit of detection was calculated to be 0.2 mM (S/N = 3). After 100 test using a same electrode, the peak current of Cl− was still 90–110% of the first time, showing the outstanding reusability. The proposed sensor was successfully applied in real water samples.