In-situ generated molecularly imprinted material for chloramphenicol electrochemical sensing in waters down to the nanomolar level

Abstract A novel device for monitoring chloramphenicol (CAP) on-site is described, making use of commercial carbon screen-printed electrodes (C-SPEs) modified with a suitable sensing element. This element consisted of a molecularly imprinted polymer (MIP), produced in-situ, by electro-polymerization. The monomers used herein were Eriochrome black T (EBT), and polymerization was conducted in acetonitrile. Raman spectroscopy followed the chemical changes occurring at each stage of the carbon surface modification. The device performance was assessed by evaluating the changes in electron transfer properties of a standard redox probe [Fe(CN) 6 ] 3− /[Fe(CN) 6 ] 4− by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and square wave voltammetry (SWV). SWV and EIS electrochemical techniques were used to calibrate the system, having standard solutions prepared under different background media (electrolyte or water coming from a home fish tank). A wide linear range was observed, with linear responses of current/resistance against log (CAP concentration) down to 10 nM. Overall, the results obtained revealed that all modifications carried out on the sensing element were effective. The final sensor provided reproducible and accurate readings and was all assembled in-situ, in a very simple and straightforward approach, most likely suitable for scaling-up, directing towards its subsequent commercial use.