Solid-phase synthesis of imprinted nanoparticles grafted on gold substrates for voltammetric sensing of 4-ethylphenol

Abstract

A voltammetric sensor based on molecularly imprinted high affinity nanoparticles has been developed for the direct, selective, and label-free detection of 4-ethylphenol (4EP). The poorly functionalised template 4EP, was successfully imprinted by the recently developed method of solid-phase synthesis of molecularly imprinted nanoparticles. These nanoparticles were grafted to the surface of gold electrodes allowing for selective and sensitive detection of 4EP. Each step of the electrode modification process was characterised by cyclic voltammetry and electrochemical impedance spectroscopy. The electrochemical response of the developed sensor was evaluated and a linear range between 0.24 and 5mgL−1 was obtained, together with good repeatability (RSD<10%). The sensor was proven to recognise specifically the target compound over structural analogues, including compounds that belong to the same metabolic pathway such as coumaric acid ethyl ester, coumaric acid and 4-vinylphenol, or other phenolic compounds such as 4-ethylguaiacol or paracetamol.