Tyrosinase based amperometric biosensor for determination of tyramine in fermented food and beverages with gold nanoparticle doped poly(8-anilino-1-naphthalene sulphonic acid) modified electrode.

The aim of the present work was to develop an amperometric biosensor for tyramine (Tyr) measurement in food and beverages. The biosensor architecture is based on tyrosinase (Tyrase) immobilization on glassy carbon electrode modified by a nanocomposite consisting of gold nanoparticles (AuNP) synthesized by a green method and poly(8-anilino-1-naphthalene sulphonic acid) modified glassy carbon electrode. Under optimized experimental conditions for fixed potential amperometric detection, the biosensor exhibited a linear response to tyramine in the range 10-120 µM and the limit of detection was estimated to be 0.71 µM. The novel platform showed good selectivity, long-term stability, and reproducibility. The strong interaction between tyrosinase and the nanocomposite was revealed by the high value of the Michaelis-Menten constant (79.3 μM). The fabricated biosensor was successfully applied to the determination of Tyr in dairy products and fermented drinks with good recoveries, which makes it a promising biosensor for quantification of tyramine.