Graphene oxide electroreduced onto boron-doped diamond and electrodecorated with silver (Ag/GO/BDD) electrode for tetracycline detection in aqueous solution

A new electrochemical sensor designed by modifying the commercial boron-doped diamond (BDD) electrode with graphene oxide (GO) reduced electrochemically and further electrodecorated with silver (Ag), named the Ag/GO/BDD electrode, was selected among a series of the BDD, GO electroreduced onto BDD (GO/BDD) and silver electrodeposited onto BDD (Ag/BDD) electrodes for the detection of tetracycline (TC) in aqueous solution. The best results regarding the sensitivity of 46.6 µA · µM −1 ·cm −2 and the lowest limit of detection of 5 nM was achieved using square-wave voltammetry (SWV) operated at the step potential of 5 mV, modulation amplitude of 200 mV, and the frequency of 10 Hz in alkaline medium. The application of the alkaline supporting electrolyte-based procedure is limited for water monitoring due to the presence of chloride that interferes with TC detection; however, it can be applied for the quantitative determination of pharmaceutical formulations. 0.1
M Na2SO4 supporting electrolyte eliminated chloride interference and can be used for the application
of Ag/GO/BDD in practical detection of TC in water.