A method for determination of xanthine in meat by amperometric biosensor based on silver nanoparticles/cysteine modified Au electrode

► XOD immobilized covalently onto citrate capped AgNPs and l-cysteine modified Au electrode. ► Constructed an improved amperometric xanthine biosensor using above electrode. ► Biosensor showed optimum response within 5 s at 0.5 V, pH 7.0 and 35 °C. ► Linear range for xanthine was 2-16 μM with a detection limit of 0.15 μM. ► Enzyme electrode lost 20% activity after 180 uses over 60 days.