Amperometric biosensor based on immobilized laccase onto Cys-Ag@Fe₃O₄ magnetic nanoparticles for selective catechol detection

This study has prepared laccase-immobilized L-cysteine functionalized-silver-coated magnetic Fe3O4 nanoparticles modified screen-printed carbon electrodes to detect catechol in the lake and tap water. Electrochemical studies showed that laccase-immobilized spherical magnetic nanoparticles (10 nm) have electrocatalytic activity towards catechol. Different parameters that influence the analytical performance of the biosensor have been studied and optimized. The catalytic current was linear for the catechol concentration between 0.1 mu M to 100 mu M (y = 7.5071x + 37.372 and R-2 = 0.9978). The detection limit of the sensor was 0.06 mu M and, the signal-to-noise ratio (S/N) was 3. The sensitivity of the sensor was 60.06 mu A.mM cm(-2). The laccase-based biosensor was performed with selective detection without interference from other substrates and matrix effect in lake and tap water. The biosensor demonstrates that it is a viable strategy for fast, simple, and cost-effective analysis of phenolic pollutants in environmental samples. Furthermore, this proposed silver-coated magnetic nanoparticles strategy can be extended to other enzyme-based biosensors as a microenvironment for enzyme immobilization and signal enhancer.

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