Immobilization of laccase on Fe3O4@MF-CNTs for the rapid and sensitive biosensing of catechol

Abstract

Rapid and sensitive detection of hazardous compounds is of great importance for sensors. This work presents the immobilization of laccase on Fe₃O₄@MF-CNTs nanocomposites (Fe₃O₄@MF-CNTs-lac) for the fast and sensitive detection of catechol. Electrochemical impedance spectroscopy (EIS) results revealed that the combined effect of Fe₃O₄@MF and carbon nanotubes (CNTs) facilitates electron transfer between laccase and the electrode. Amperometric curves indicated that the Fe₃O₄@MF-CNTs-Lac biosensor can respond rapidly to a substrate and detect catechol within 0.5 s. The Fe₃O₄@MF-CNTs-Lac biosensor possesses a low detection limit of 0.84 μM (S/N = 3) with a linear range of 1–3000 μM, as well as high sensitivity, remarkable organic compound tolerance, and good selectivity, reproducibility and stability. The catechol biosensing assays revealed that Fe₃O₄@MF-CNTs-Lac can be operated in acidic water environments. Most importantly, the Fe₃O₄@MF-CNTs-Lac biosensor exhibited reliable results in real water sample analysis. The outstanding biosensing performances reveal that the Fe₃O₄@MF-CNTs-Lac biosensor has a technical application in the treatment of catechol to avoid catechol pollution.