Disposable biosensor based on nanodiamond particles, ionic liquid and poly-l-lysine for determination of phenolic compounds

This study describes the development of a highly sensitive amperometric biosensor for the analysis of phenolic compounds such as catechol. The biosensor architecture is based on the immobilization of tyrosinase (Tyr) on a screen-printed carbon electrode (SPE) modified with nanodiamond particles (ND), 1-butyl-3-methylimidazolium hexafluorophosphate (IL) and poly-l-lysine (PLL). Surface morphologies of the electrodes during the modification process were evaluated by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to investigate the electrochemical characteristics of the modified electrodes. Owing to the synergistic effect of the modification materials, the Tyr/PLL/ND−IL/SPE exhibited high sensitivity (328.2 μA mM−1) towards catechol with a wide linear range (5.0 × 10−8 – 1.2 × 10−5 M) and low detection limit (1.1 × 10−8 M). Furthermore, the method demonstrated good reproducibility and stability. The amperometric response of the biosensor towards other phenolic compounds such as bisphenol A, phenol, p-nitrophenol, m-cresol, p-cresol and o-cresol was also investigated. The analytical applicability of the biosensor was tested by the analysis of catechol in tap water. The results of the tap water analysis showed that the Tyr/PLL/ND−IL/SPE can be used as a practical and effective method for catechol determination. [Display omitted] •A novel amperometric catechol biosensor based on tyrosinase was developed.•Tyrosinase was immobilized on nanodiamond, ionic liquid, poly-l-lysine modified screen-printed carbon electrode.•The biosensor showed high sensitivity towards catechol.•The amperometric response of the presented biosensor towards other phenolic compounds was also investigated.•The biosensor was successfully applied for catechol determination in tap water.