Organic-phase enzyme electrode for phenolic determination based on a functionalized sol–gel composite

An amperometric biosensor for monitoring phenols in the organic phase was constructed by the silica sol–gel immobilization of tyrosinase on a glassy carbon electrode. The organic–inorganic hybrid materials with different sol–gel precursors and polymers were optimized, and the experimental conditions, such as the effect of the solvent, operational potential and enzyme loading were explored for the optimum analytical performance of the enzyme electrode. The biosensor can reach 95% of steady-state current in about 18 s, and the trend in the sensitivity of different phenols is as follows: catechol>phenol>p-cresol. In addition, the apparent Michaelis–Menten constants (Kmapp) and the stability of the enzyme electrode were discussed.