Effect of Acridine Orange on Improving the Electrochemical Performance of Tyrosinase Adsorbed Sulfide Minerals Based Catechol Biosensor

Abstract A highly sensitive and selective electrochemical biosensor for catechol (CC) detection was developed by immobilizing tyrosinase (TYR) on a glassy carbon electrode (GCE) modified with sulfide minerals (SFMs) in the co‐adsorption of acridine orange (AO). The sensor employed natural SFMs as the substrate material and utilized AO as a molecular recognition probe to create synergy effect for TYR to detect catechol. The developed TYR/AO/SFMs/GCE biosensors were characterized by scanning electron microscope, energy dispersive analysis of X‐rays spectroscopy, X‐ray diffraction spectra, X‐ray fluorescence, and electrochemical analysis. The results show that the sensors have excellent electrochemical activity for the detection of catechol (CC) under optimized conditions. The linear ranges were 0.1–50 μM, 0.1–10 μM, 0.1–50 μM and 0.1–100 μM for galena, pyrite, chalcopyrite and sphalerite, respectively, with the detection limits of 1.18 μM, 0.29 μM, 0.54 μM and 0.68 μM, respectively. The sensors also have good reproducibility, stability, repeatability and anti‐interference ability. AO is essential to increase the adsorbed amount and provides suitable orientation of the adsorbed TYR on these sulfide minerals’ surfaces. In consideration of cost‐effective and rich resources of sulfide minerals, easily physical adsorption method, combination of organic dye, minerals and enzymes, this strategy paves a new way to design other novel electrochemical biosensors.