▎ 摘　　要

NOVELTY - Preparation of chemically modified electrode comprises uniformly dispersing nitrogen-doped graphene in water, dissolving potassium ferrocyanide and potassium chloride in hydrochloric acid, dissolving ferric chloride and potassium chloride in hydrochloric acid, placing in water bath, adding third solution and second solution to first solution, stirring, separating, washing, drying to obtain Prussian blue/nitrogen-doped graphene nanocomposite material, dispersing nanocomposite material in N,N-dimethylformamide, taking dispersion solution, coating on surface of glassy carbon electrode and drying. USE - Method for preparing chemically modified electrode for electrochemical sensor used for detecting tyrosine (claimed). ADVANTAGE - The method has low detection limit, wide detection range, good stability, and strong anti-interference performance and reproducibility. DETAILED DESCRIPTION - Preparation of chemically modified electrode comprises uniformly dispersing 40-60 mg nitrogen-doped graphene in 40-60 mL water to form first solution, dissolving 10-11 g potassium ferrocyanide and 0.7-0.8 g potassium chloride in 8-12 mL hydrochloric acid to form second solution, dissolving 0.1-0.2 g ferric chloride and 0.7-0.8 g potassium chloride in 8-12 mL hydrochloric acid to form third solution, placing in water bath at 30-40 degrees C, adding third solution and second solution to first solution at speed of 300-600 mu L/minute, stirring for 20-60 minutes, separating reaction liquid, washing, drying to obtain Prussian blue/nitrogen-doped graphene nanocomposite material, dispersing 2-5 mg Prussian blue/nitrogen-doped graphene nanocomposite material in 4-8 mL N,N-dimethylformamide, taking 5-8 mu L dispersion solution, coating on surface of glassy carbon electrode with diameter of 2-5 mm and drying.