Green preparation of chlorine-doped graphene and its application in electrochemical sensor for chloramphenicol detection

A green but efficient synthesis approach for chlorine-doped reduced graphene oxide (Cl-RGO) was developed. The chlorine-doping and reduction was achieved in one-step by refluxing graphene oxide solution in concentrated hydrochloric acid (8 M, 120 °C) under N2 atmosphere. X-ray photoelectron spectroscopy analysis revealed that the Cl content was 1.01 at.% in the Cl-RGO. Electrochemical measurements indicated that the Cl-RGO modified glass carbon electrode showed enhanced electrochemical conductivity and electrocatalytic activity for the veterinary drug chloramphenicol (CAP) detection. Thus a highly selective electrochemical sensor for CAP was constructed based on Cl-RGO, and a linear relationship between current intensity and CAP concentration (2–35 μM) was obtained with a detection limit of 1 μM (S/N = 3). The sensor showed excellent reproducibility, storage stability and was successfully used for CAP detection in milk, calf plasma, water and pharmaceutical samples.