A phenol biosensor based on immobilizing tyrosinase to modified core-shell magnetic nanoparticles supported at a carbon paste electrode |
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Authors: | Zhimin Liu |
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Institution: | State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, People's Republic of China |
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Abstract: | A phenol biosensor was developed based on the immobilization of tyrosinase on the surface of modified magnetic MgFe2O4 nanoparticles. The tyrosinase was first covalently immobilized to core-shell (MgFe2O4-SiO2) magnetic nanoparticles, which were modified with amino group on its surface. The resulting magnetic bio-nanoparticles were attached to the surface of carbon paste electrode (CPE) with the help of a permanent magnet. The immobilization matrix provided a good microenvironment for the retaining of the bioactivity of tyrosinase. Phenol was determined by the direct reduction of biocatalytically generated quinone species at −150 mV versus SCE. The resulting phenol biosensor could reach 95% of steady-state current within 20 s and exhibited a high sensitivity of 54.2 μA/mM, which resulted from the high tyrosinase loading of the immobilization matrix. The linear range for phenol determination was from 1 × 10−6 to 2.5 × 10−4 M with a detection limit of 6.0 × 10−7 M obtained at a signal-to-noise ratio of 3. The stability and the application of the biosensor were also evaluated. |
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Keywords: | Magnetic bio-nanoparticles Tyrosinase Biosensor Phenol |
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