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The determination of phenolic compounds has attracted considerable attention in the analytical chemistry field because of their high toxicity and detrimental effects to human being health. At present, an electrochemical biosensor has been proven to be an accurate and versatile analytical method for the detection of phenolic compounds, due to such advantages as high selectivity, relatively low cost, and the miniaturization and automation. 1–3 More recently, various supporting materials, such as graphite composite, 4 conducting polymer, 5, 6 sol-gel films, 7, 8 and self-assembled monolayers (SAMs), 9 have been successfully utilized to immobilize enzymes for the construction of a tyrosinase (tyr)-based electrochemical biosensor. Among them, sol-gel film offers a better biointerface for the immobilization of enzymes. The encapsulated enzymes retain the same functionality in comparison with their free-enzymes. However, the apparent activity of the entrapped enzymes is often hindered by the diffusion of the analyte and the product in sol-gel matrices, 10, 11 especially for a larger dimension analyte and product, due to a larger diffusion resistance. To achieve a highly sensitive biosensor, the signal amplification and the stable immobilization of the enzymes on the transducer surface are of considerable importance. In recent decades, metal nanoparticles have been successfully utilized to improve some biomolecular immobilization and bioassay methodologies due to their unique chemical and physical properties. 12, 13 Especially, gold nanoparticles (AuNPs) have been widely used in the fabrication interface of biosensors to enhance their electronic …