Development of an impedimetric sensor based on carbon dots and chitosan nanocomposite modified electrode for Cu(II) detection in water

Abstract

The fast and sensitive detection of copper ions would be essential for water monitoring. Herein, we report a novel development of an impedimetric sensor based on carbon dots/chitosan nanocomposite. Carbon dots (CDs) were synthesized by simple heating of an acidic aqueous solution of glucose. The prepared CDs were characterized by TEM, FTIR, XRD, UV-visible, and PL. These measurements revealed that the CDs possess a mean size of 3.2 nm, a graphitic structure with carboxyl and hydroxyl groups on the surface, and shows particular optical properties. A glassy carbon electrode (GCE) was modified with a carbon dot/chitosan nanocomposite and was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The CDs-CHITO/GCE electrode exhibits a large surface area, good conductivity film, and charge transfer at film/electrolyte interface. The proposed impedimetric sensor exhibits a linear response to Cu(II) ranging from 10−9 M to 10−5 M with a detection limit about 5 × 10−10 M. In addition, the sensor shows a good selectivity toward Cu(II) ions, which is less than 5%. Therefore, the as-developed impedimetric sensor exhibits good reproducibility, stability, selectivity, and a low limit of detection, which augur well for its application in water safety control processes.