Fabrication of sulphur-doped graphitic carbon nitride anchored Ag@AgCl electrocatalyst for the sensing of chloramphenicol.

We have developed sulphur-doped graphitic carbon nitride (S-GCN) anchored Ag@AgCl electrocatalyst through a green technique for the first time for the electrochemical sensing of chloramphenicol. The Ag@AgCl nanoparticles were synthesized using Rhoeo discolor (Tradescantia spathacea) plant extract without the use of any external halide source. As per our knowledge, this is the first time Rhoeo discolor (Tradescantia spathacea) plant extract was used for the synthesis of Ag@AgCl nanoparticles without the use of any external halide source. Using sonochemical technique, the green synthesized nanoparticle was combined with S-GCN to form Ag@AgCl/S-GCN electrocatalyst. The synthesized materials were characterized by suitable techniques such as UV-visible spectroscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and elemental analysis. The electrocatalytic reduction mechanism of chloramphenicol was studied with the help of electrochemical impedance spectroscopy, cyclic voltammetry, and linear sweep voltammetry. The Ag@AgCl/S-GCN modified electrode has shown a linear response in the range of 1 to 650 μM, with a LOD of 420  $\text{nM}$ . Further, the practical application of the developed sensor was analyzed using real samples such as milk and honey and satisfactory recovery rates were observed.